I test run an invoice entry using \invoices\samdata. The distribution code Pro200 is selected and I enter 1000.00 and tax of 47.62 is calculated at 5%.The total invoice amount
and discount base is 1000.00. I require that the tax of 50.00 be calculated instead and
the total invoice value and the discount base be 1,050.00. The final accounting entries will be debit AR 1,050.00, Credit Income 1000.00, Credit GST 50.00
Your help is appreciated.

Hello Stanley:

Using your example in Receivables invoice entry, you would enter the amount including the tax amount. You would enter $1,050 and the results would be as you require.

Though that the program computes 5% on 1,000.
Answer found by setting up a distribution code pointing the account to
Sales
Tax type "Total include Sales"
GL tax account to "Output Tax" (for Malaysian GST)

Terima kasih (Thank you)