INDEX/MATCH combo with using nth result

Hi there,

I am trying to set up a tracking sheet so I can track test results for an asset base. The asset base is in excess of 700K so trying to do horizontal matching and I am having some issues I cannot wrap my head around.

Trying to track the below:
- latest successful test year (seems to work)
- previous test year (can't get a horizontal match function to work on 2nd highest year)
- time between tests (latest - previous[if I could get it too work...])
- Removal Year (works only when there is a single pass result, doesn't work if multiple PASS results are in the same row....)

I have attached the redacted dummy spreadsheet above. Any help would be very much appreciated.
Cheers,
Hearny