Request to add custom field calculations in invoices

[BawarYassin]

Some businesses charge customers based on design and calculated size or volume which is not fixed and changes for each purchase thus making it impossible to create inventory item for each purchase.
Manager needs to allow such calculations in Sales and Purchases for this matter.
See example below for a CNC machined 2 millimeter door panel.

[shahabb]

Abitlity to save formulas/logics in form defaults and option to make fields uneditable

Hello everyone. I did a quick search and this idea is already discussed on some level such as payslip. I dont know how hard this would be to implement. But i wanted to discuss it atleast. My idea is to have formula/logics/number etc saved in form defaults, id of every field visible and calculation could be done by calling value from other fields. (example field.qty or customfield.xyz). This way we can automatically select tax code for different customers. Lets say different tax codes apply to …

Already suggested this a few months ago. Still it isnt even in ideas
I hope it is implemented someday.