You have specifically excluded values less than 0 by using the criteria ">=0"

Why not just use...
=SUMIFS(B$25:B$38,$I$25:$I$38,$A$1,$A$25:$A$38,$A6)

If you dont want 0 to show, then adjust that to...
=if(SUMIFS(B$25:B$38,$I$25:$I$38,$A$1,$A$25:$A$38,$A6)=0,"",SUMIFS(B$25:B$38,$I$25:$I$38,$A$1,$A$25:$A$38,$A6)