Hi,
I'm really sorry but you've lost me completely....

With Lookup and Lookup2 nothing is compared to anything. They both retrieve the value in the list that the index-variable points to and puts that value in the varible specified after the list itself.

So...
Code:
i VAR Byte
j VAR Byte
i = 0
Lookup2 i, [10, 20, 30, 40, 50], j   'This will return 10 in variable j

i=3
Lookup2 i, [10, 20, 30, 40, 50], j   'This will return 30 in variable j

i=10
Lookup2 i, [10, 20, 30, 40, 50], j   'This will leave j unchanged since there's only 5 entries in the list.
If you want to look/search for a specific value in the list you can use Lookdown and/or Lookdown2 instead.
Code:
i VAR Byte
j VAR Byte
i = 20
Lookdown i, [10, 20, 30, 40, 50], j   'This will return 1 in variable j

i=50
Lookdown i, [10, 20, 30, 40, 50], j   'This will return 4 in variable j

i=12
Lookdown i, [10, 20, 30, 40, 50], j   'This will leave j unchanged since 12 is not present in the list.
I'm sorry if this is of no help to you but I simply don't understand the question :-/

/Henrik.