It is not.
You are wrong in calculating price w/o tax.
Proper formula is:
120 * (1.27 / (1 + 14 / 100)) = 133.68
To explain...if we take your price w/o tax and add 13% tax to it we will get:
131.064 * 1.14 = 149.41
149.41 / 120 = 1.245 as a price / unit instead of 1.27
I dont understand.
Why 152,4-(152,4*14%) = 131,06400 so the same 120*(1,27*(86/100)) = 131,06400 is incorrect?
In my opinion your formula is incorrect.