Just noticed on the 2023 To 2024 NHRA Rule Amendments the addition of the following language:
SECTION 2: RACE PROCEDURES, SINGLE RUNS (Page 8) (11/29/2023) In situations where a driver is making a single run, he or she is considered the winner once he or she stages and receives the start signal or is declared the winner by the official starter. If a competitor crosses the boundary line on a single run, the elapsed time is voided for lane-choice determination.
Drivers who run under elapsed time barriers outlined in their category are disqualified even if on a single run.
My interpretation is that if you are in a single run, you cannot run under the index any longer?