Adjusting Tax

I am using MYOB Business Pro.

When creating an Invoice, why can't MYOB add a simple feature that allows you to manually adjust the Tax field to reflect the exact GST amount on an invoice?

It would save customers significant time in adding description lines for GST-free items, and working out what portion of services/disbursements are GST-free.

This feature was available on primitive desktop versions, but why not on the current web versions in this modern day. Surely MYOB knows that not all services/items in Australia have GST, there are GST-free items, or a combination of GST/GST-free items too.

Frustrated at the lack of development for a major accounting software provider.