Keep your numbers straight.
Is the discount 1.115% or 1.116%?
Why is the discount 5 cents instead of 7 cents?
The discount is applied to the tax not the full value so your formula is:
(4.3 + 1.7)*(100-1.116) = 5.9304%
which is the correct payable on your $100 sales…$5.93 total tax.