Production Incentive 2055 is coming through info type 15 here question give us the details how exactly it is being created in 0015 i.e whether you are maintaining a record in 0015 by using field Number/Unit or Amount if you are passing Number/Unit then we have to Query NUM of 2055.
WGTYP
NUM?0
<
ADDWT *
=
ADDWT *
>
PCY Z888
Where in case record is maintained with amount field then use operation AMT?0 rest logic is same.
Further more if wage type 2055 is not maintained in 0015 i.e no record since Input table will not have 2055 in that case Z777 itself will not execute why we are querying the value with 0 is if by mistake any value is being maintained with negative indicator then it checks and allows the calculation if it is greater than "0".
before doing all this give us clarity wage type 2055 is passed to variable &2055 (ADDWT&2055)or not if not no point in using operation AMT=&2055 if you are passing then only you can use AMT=&2055.
Regards
Venkatesh