Returning the range for a specific value

umasirhcAssuming I understand your need, I would:

1) Add two helper columns to Table1: Row, Column

2) Row's purpose is to find the row in Table2 using formula:

=MATCH([@[MED_TRUE]],Table2[MED_TRUE],0) 

3) Column's purpose is to find the first match lower than DOSE_TRUE using formula:

=MATCH([@[DOSE_CALC]],OFFSET(Table2,[@Row]-1,0,1,COLUMNS(Table2)-1),1)

4) Now add NRST_VLS_DOWN using formula:

=INDEX(Table2,[@Row],[@Column])

5) Finally add NRST_VLS_UP using formula:

=INDEX(Table2,[@Row],[@Column]+1)

See attached. This is the solution that came off the top of my head. It works but I feel like there is a simple solution out there. Hopefully someone else will provide it.