Hi Bob FOFC,
Welcome to Community! QuickBooks Online Advanced is designed so you can spend less time on repetitive tasks and focus more on the insights you need to grow your business. Reaching product limitations can be concerning in situations such as this. I'll be happy to provide some insight here!
You've mentioned your current plan has reached the limit of 40 classes. With QuickBooks Online Advanced, Classes and Locations (combined) will be unlimited. Coming soon, you'll see a new tab in your Account and Settings section that will show your current usage and your plan's usage limits.
In your situation, I suggest reviewing the classes you currently have and make any that you're not using inactive. This will free up space if you need to add other classes. Here's how:
1. Click on Settings ⚙ in the top right
2. Select All lists
3. Open Classes
4. Use the ▼ dropdown menu in the Action column for the class you want to Make inactive
5. Hit Yes to confirm.
Please feel free to reach back out if you have additional questions or concerns. We'd be glad to assist!