I have ever put an question in SCN in order to know how to calculate "Date Total" in month: in Feb just only 28/29 days, Mar normally is 31 : http://scn.sap.com/thread/2033597
However there was no good solution :( After that I have found a suitable solution to fit this requirement. I'd like to share it for you. Because I think whenever we touch Time Evaluation, this requirement will be requested from our customer.
Now let's start with the main important part in my solution. It's a PCR: creating 1 PCR in T-Code PE02:
ZCOU Calculate total date in month
ADDDB9W99Z Set day balance = 0
YXED mean: we will use the End date of Time Period - X (01.01.2000 it's constant), then assign to HRS.
YXBD: the same meaning with YXED but not last date, It's Begin date of Time Period.
next I will use current value in HRS + 1 and then add this value into Time Type 9W99.
Now just run and check time results. Hope it's correct. I will check for 4 month: Jan-2012, Feb-2012, Mar-2012 & Apr-2012. After running PT60, my results are 100% correct as below:
Jan-2012: it's 31 days
Feb-2012: it's 29 days
Mar-2012: It's 31 days
Apr-2012: It's 30 days.
As you can see, I only you standard operation / Function in SAP to resolve this issue.