Capturing Top 5 Performers

I'm using the LARGE function to find the top five values (number) in column
"F" of a large list and place those values in Cells N1 thru N5 — Cell
N1=LARGE(F1:F100;1) thru Cell N5=LARGE(F1:F100;5).
Having found these values I want to associate them with the related text in
column "A" of that list so that I can correlate the sales figures with the
related salesmen (from column A) in cells M1 to M5. I used the LOOKUP
function to do that — M1=LOOKUP(N1;F1:F100;A1:A100) thru
M5=LOOKUP(N5;F1:F100;A1:A100).

I have two problems:
First - two salesmen have the same sales figures and the LARGE function
seems to arbitrarily distinguish them as the #1 and #2 top salesmen (although
I'm not really sure of that)
Second - the LOOKUP function is not returning expected results with two
variations
(a) cells M1 and M2 do not distinguish between top salesmen #1 and #2 and
returns #1 in both cases
(b) some returns from the list of salesmen do not correlate to their sales
totals

Can anyone help me sort this out?