Hello,
The calculation of accrual/deferral will check the "calculation from" and "calculation to" date of the profit related flows - here the interest flows. Screenshots with these information (TPM13 or FTR_EDIT "cash flow" tab with calculation view) and the simulation of TPM44 for key date 31.12.2012 will help to understand the issue. Would you please provide the screenshots ?
Best regards,
Jasmine