Although the amounts in the PA may contain decimals, the values in the Annual Plan Table 17 should not have decimals. This is controlled by validation rule 2.61:
2.61 validate that in Table 17, the Main Allocation and the Performance Reserve amounts have no decimals (error) "The annual financing plan must be in euros, without decimals".
Following an internal discussion between the different DGs has been agreed that the programming and the commitments should be rounded to the euro as it has been done in the 2007-2013 period and not in cents. Total allocation in euro should also be respected.
This means that the performance reserve might not be exactly at 6% with this rounding to the euro. In that case the figures should be rounded to the closer euro or at least not to diverge by more than 99 cents from the 6%.
The main reason for being stricter with the OP is that the financial plan of the OP (namely Table 17) is the basis used for the commitments in the EU budget unlike figures in PAs. DG BUDG has reaffirmed this though line on OPs.
Only Table 17 must be rounded to the Euro. All other tables can have decimals, although their totals must be consistent between the different tables! So there's no problem in having decimals in Tables 18a, 18b and not in Table 17 as long as the total sum per Fund/Category of Region of Tables 18a and 18b has no decimals.