For expenses you should be able to enter the total amount of an expenses and pick the tax associated or have a default tax settings and the tax filed and subtotal should be calculated. If someone needs to make changes they should be able to override the calculation just by changing the field. Manually entering data in all 3 fields is time consuming.
Their should also be a save & new button at the bottom to move right into the next expense.
Thank you for this valuable feedback, we will consider it for future development.