sorry if this is the 2nd post for same question, cant find the 1st post

i have this formula for items per hour.

=SUMPRODUCT(--$A$2:$A$1000=$B2),--($A$2:$1000<$B3))

the data is items per hour, time is military 00:00 to 23:00
formula calculates properly with exception of 23:00 which returns 0.
i have tried different variations of the formular all with the same results
thanks in advance for your help.
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dr350x