I appreciate the screenshot you've provided, talk2khurram.
The maximum # of G you can enter is up to 10000 grams since the system is unable to calculate beyond 5 decimal places.

I appreciate you explaining how it would help you out. While that feature isn’t currently in our development roadmap, we are working on big improvements that will be helpful for the majority of our customers.
You can visit the What's New section on your QuickBooks Desktop, to be updated with our latest news and updates including product refinement.

Additionally, I recommend visiting this link: Resource Hub. This will provide you with resources and videos about managing your QuickBooks Desktop account, income, expenses, inventory, and running reports.
If you have any other questions or need anything else in QuickBooks, let me know in the comment below. I'll be more than happy to help you in any ways I can. Have a lovely day!