how to add aggr function in expression

[#1]

Hi Guys, could you please help me to add aggr on this expression?

Only({<AR_OF_LUXEVENT_HIST.USR_PERHIS_ESTADO={'200'}>}AR_OF_LUXEVENT_HIST.USR_PE_FECMOD)-Only({<AR_OF_LUXEVENT_HIST.USR_PERHIS_ESTADO={'150'}>}AR_OF_LUXEVENT_HIST.USR_PE_FECMOD))*24

i tried with:

1)  aggr(((Only({<AR_OF_LUXEVENT_HIST.USR_PERHIS_ESTADO={'150'}>}AR_OF_LUXEVENT_HIST.USR_PE_FECMOD)-Only({<AR_OF_LUXEVENT_HIST.USR_PERHIS_ESTADO={'0'}>}AR_OF_LUXEVENT_HIST.USR_PE_FECMOD))*24),AR_OF_LUXEVENT_HIST.USR_PERHIS_NEGOCI)

2) (aggr((Only({<AR_OF_LUXEVENT_HIST.USR_PERHIS_ESTADO={'150'}>}AR_OF_LUXEVENT_HIST.USR_PE_FECMOD),AR_OF_LUXEVENT_HIST.USR_PERHIS_NEGOCI) - aggr(Only({<AR_OF_LUXEVENT_HIST.USR_PERHIS_ESTADO={'0'}>}AR_OF_LUXEVENT_HIST.USR_PE_FECMOD)),AR_OF_LUXEVENT_HIST.USR_PERHIS_NEGOCI)*24

thanks!

gerardo