Limitations when Combining OFFSET and MATCH to return a cell reference

Hello. I'm attempting to retrieve multiple row numbers for a range of data
using MATCH and OFFSET. The file works perfectly for the first few items,
but then it stops and leaves off the remaining references.

The following formula is placed in cell A9:
=IFERROR(A8+MATCH(L$5,OFFSET('Collector Historical'!AK1,A8,0,10000,1),0),"")

Collector Historical is the tab where all my detail resides. G1, is the
first cell in the column that will be searched.

L$5 is a date and name concatenation that is used to lookup a supervisor's
name and the date of the reporting. For example, 39692CF, means I want
the formula to return the first reference for CF's September 2008 data.

In my example, CF has 13 collectors reporting to him, the first cell
reference is 1107. I drag the formula down and expect to see numbers 1029
through 1041. Instead, I only get numbers 1029 through 1035 (7 items)...

I changed the supervisor name to obtain a different lookup, picking a
supervisor with less subordinates to see if it gives me all of the
subordinate references. No luck...I picked a person with only 7 subordinates
and it returns the first 4 references (i.e., SM) .

I'm attaching a sample worksheet....

Can someone tell me what I'm doing wrong? Thanks in advance....