Need Help Counting Specific Times In Filtered Table

hi there. the error was due to your range not being the same:
=SUMPRODUCT(SUBTOTAL(103,OFFSET(A1,ROW(D19:D5018)-ROW(A1),0)),--(D19:D5019<"00:30"))

if you change that, you do get a number, but a wrong one:
=SUMPRODUCT(SUBTOTAL(103,OFFSET(A1,ROW(D19:D5019)-ROW(A1),0)),--(D19:D5019<"00:30"))
that's because of 2 reasons;
1) putting double quotes makes Excel read it as a text. and texts are regarded as being bigger than numbers. hence D19:D5019 (time is regarded as numbers) is always going to be lesser than "00:30" (a text). you can convert it into a number by a few ways:
TIMEVALUE("00:30")
"00:30"+0
--"00:30"
2) "00:30" is 30 minutes, not 30 seconds. 30 seconds is "00:00:30"

so your final formula should look like:
=SUMPRODUCT(SUBTOTAL(103,OFFSET(A1,ROW(D19:D5019)-ROW(A1),0)),--(D19:D5019<--"00:00:30"))

you could also help us by manually typing what the desired answer should be. is it 20? 20 is found in cells xx, xx, xx, etc. you can look at my signature for some tips.