What is happening in my spreadsheet?

[willemeulen]

In two different spreadsheets I calculate the same figures with a slightly
different approach. One being a summary sheet of all certificates and other
one being a cash flow. Because of the rounding and different calculations i
get slight differences up to 3 cents. This is accepted. But for some reason
now the differences are up to 17.50 and 35 dollars. On the same sheet i do
the same exercise but now by doing smaller steps and get different answers!?

What is causing this?! What should I look for? please help

 

[Bernard Liengme]

We would need more details to be able to offer suggestion.

 

[willemeulen]

Value of work done (V), contract price adjustment(CPA), Retention(R),
Penalty(P) all input values except R which is 2,5% from V + CPA. All values
mentioned before are split in 2 cells, one for repair period and another for
maintenance but will keep it as one for explaination.

In the first instance I calculate as VAT (value added tax) follows
(V+CPA-R-P*14%)

Because I get bigger disrepency's than normal I recalculated the same VAT in
steps in order to find the fault. Keep in mind I'm using the same input
values by reffering to the cells.

(V+CPA)
next cel
Answer 1 - R and P
next cell
Answer * 14%

Now I get a different answer( differences from 35 dollars etc) with previous
calculation and that on same sheet and same input?! I mean the figures I am
using are big, VAT runs up to 270.000. And I use roundings to 2 digits.
Couple of cents I understand but this?!

Hope this helps

 

[JGreg7]

Watch the order of operations, and add parenthesis to force the order.
Example: =8+5*2 does not give the result same values as =(8+5)*2