PO roundings (ME21N - MIRO)

Question

Hi Guru,
Iu2019ve a problema with PO roundings.
Our situation is as follows:
we manage MM in the public sector integrated with FI - FM - CO - SP - SD.
Even with ECC 4.6 we had problems on the rounding of prices for individual positions in the Purchase Orders (ME21N) and invoices (MIRO), the problem is now with ECC 6.0.
PROBLEM
When creating the purchase order and goods receipt, the system calculates the total value of VAT purchases in a manner different from that determined during invoice entry. In the first case, purchase order, the VAT amount is calculated and rounded at each item; in the second case, invoice entry, the amount is calculated and rounded at header level. This mechanism can cause problems of mismatch between tax amounts calculated in purchase order and amounts calculated in miro.
EXAMPLE:
u2022 In purchase order (and goods receipt):
Example:
Item 1: 83.78 * 20% = 16.756 -> rounds to 16.76 
Item 2: 83.78 * 20% = 16.756 -> rounds to 16.76 
Total VAT: 16.76 + 16.76 = 33.52
total financial commitment (earmarked fund) to consume = total PO = 201.08
u2022 During invoice entry:
Example:
Item 1: 83.78
Item 2: 83.78
Total VAT 167.56 * 20% = 33.512 -> rounds to 33.51
total financial commitment (earmarked fund) to consume = total PO = 201.07
From the fact that the VAT amount is calculated correctly in MIRO, we want to align the two methods of calculation, so: total amount of VAT PO = 33.51 and  not 33.52 (for us it is essential that the system correctly calculate the VAT already in the PO for the integration with the earmarked fund).
Hoping that it was not too wordy or so exhaustive,
Thank you in advance,

Answer 1

Hi,
It's a problem related with rounding in header conditions. In tcode M/06, in group conditions you can manage this issue. It use to happens when you have a lot of items in a document and with large amounts.
For a futher information, you can see these notes:
Note 315792 - Group conditions of the same amount on item
Note 80183 - Rounding
Note 517829 - Source code f new dstrbtn rule 'roundng diffrnce comparison'
and related notes
I hope this helps you
Regards
Eduardo