The formula checks if either of these combinations of 3 criteria are TRUE or FALES

ISNUMBER(SEARCH("U",$G3)),S$2>=$H3,S$2<$I3

ISNUMBER(SEARCH("U",$J3)),S$2>=$K3,S$2<$L3

if either combination is true, then "x" is returned, else a blank.

Is that the correct logic?