Short answer
An ERP add-on module fits when your data is clean and your process matches what the module expects. A custom AI tool on top of your existing ERP fits when your quoting or scheduling rules are specific to your shop. It suits shops that would rather pay once and own the code than pay a yearly fee. Lattice Partners is an AI implementation partner based in Los Angeles and New York that helps companies build an AI strategy, trains their teams on AI tools, and builds custom agents and software.
- Compare the total cost over the years you'll use the tool, not the first-year price.
- A custom tool reads from and writes to the ERP you already run, so you don't have to replace it.
- Check what your current ERP license already includes before you buy anything new.
What is an ERP add-on module?
An ERP add-on module is an extra feature set the vendor sells on top of the core system. Examples include quoting, scheduling, and configure-price-quote (CPQ). It's built around the vendor's own data model and is usually licensed by the year.
NetSuite's own CPQ page says "NetSuite CPQ is available as an add-on module" (NetSuite). NetSuite's site also says customers subscribe for an annual license fee made up of the core platform, optional modules, and the number of users. Other ERPs used by fabricators, such as Epicor, Acumatica, and JobBOSS, have their own packaging, so read your own contract.
How do the two options compare?
The two options differ most in cost model, fit with your process, and who maintains the result. The table summarizes them.
| Factor | ERP add-on module | Custom AI tool on your ERP |
|---|---|---|
| Cost model | Yearly license on top of the ERP | One-time build, plus upkeep you choose |
| Fit with your process | Built around the vendor's workflow | Built around how your shop quotes and schedules |
| Messy data (old quotes, folders, email) | Usually needs clean ERP records | Can read old quotes, PDFs, and spreadsheets |
| Ownership | Vendor owns the software; you rent access | You own the code |
| Maintenance | Vendor updates the module | You or your builder maintain it |
| Speed to start | Depends on the vendor's setup process | A first version usually ships in a few weeks |
| Best when | Data is clean and the process matches | Rules are specific and data is scattered |
For ranges on what a custom build typically costs, see How Much Does AI Consulting Cost?.
When does an add-on module make sense?
An add-on module makes sense when your process is close to the vendor's standard and your ERP data is already clean. You get vendor support, regular updates, and a feature that's tested across many customers.
It's also the faster choice if you don't want to own any software. If your quoting follows standard rules and you're happy with the module's workflow, paying a yearly fee can be reasonable.
When does a custom AI tool make more sense?
A custom tool makes more sense when your rules are specific, your data is scattered, or you don't want another recurring license. It sits on top of the ERP you already run, so your data stays where it is.
Three signs point toward custom:
- Your quoting depends on judgment. Estimators use rules and comparisons that a standard module can't express.
- Your data lives outside the ERP. Past quotes sit in folders, spreadsheets, and email.
- You want one view. The office and the floor should see the same job status.
Examples include drawing-to-estimate tools, quoting, and production scheduling built around your own rules.
How do you compare the cost of the two options?
Compare the total over the years you expect to use each one. A module costs its yearly fee every year. A custom build costs once, plus any upkeep.
Use this simple comparison with your own figures:
- Module total = yearly module fee × years of use + setup cost.
- Custom total = one-time build + yearly upkeep × years of use.
Ask each vendor for the numbers in writing, including any change to your user count. Then check what your current ERP license already includes. You may already own a scheduling or quoting feature you haven't turned on.
"We've built into a variety of ERPs, like Acumatica and Sage, and a lot of them end up being similar to plug into. Our approach is usually an automation that feeds the ERP, or sometimes a standalone tool."
Martin Anquetil, Co-Founder and Managing Partner, Lattice Partners
How Lattice Partners does this
Lattice Partners builds custom quoting, scheduling, and job tracking tools for metal fabricators and job shops. The tool connects to your ERP, timekeeping, and purchasing records and works alongside them. We don't ask you to replace your ERP.
In Learn, we sit with your estimators and planners to see how work gets done. Tailor writes your rules down with them. In Build and Ship, we aim to have a first version within a few weeks. Iterate improves it from real jobs over 2 to 3 rounds. If an add-on module would serve you better, we say so.
Custom software is a one-time build and the client owns the code. We don't charge a recurring per-seat or per-module license. The manufacturing page shows our work with shops.
Frequently asked questions
Should I buy my ERP's quoting module or build a custom tool?
Buy the module if your process matches it and your data is clean. Build a custom tool if your rules are specific, your data is scattered, or you'd rather pay once than every year.
Does a custom AI tool replace my ERP?
No. A custom tool reads from and writes to the ERP you already run. Your ERP stays the system of record.
How do ERP vendors charge for add-on modules?
It varies by vendor. NetSuite says its license is an annual fee covering the core platform, optional modules, and the number of users. Check your own contract for the details.
Who maintains a custom AI tool?
You own the code, so you or a builder you choose maintains it. Lattice Partners can stay on after launch to support and improve what we built.
Can a custom tool work with messy data?
Yes. A custom tool can read old quotes, PDFs, and spreadsheets that an ERP module usually can't. Cleaner inputs still give better results.
Related reading
About Lattice Partners
Lattice Partners is an AI implementation partner based in Los Angeles and New York. We help companies build an AI strategy, train their employees on AI tools like ChatGPT and Claude, and build custom AI agents and software. Clients own the code we build. Lattice Partners was founded by Colin McDonnell, Martin Anquetil, and Christian Yeghnazar. Contact us to talk about your use case.