'should of' really should be 'should have'
Well it was 22:53 afterall!
Loosing that hour in bed with the clocks changing obviously took its toll!
OK, you're in a general aviation environment dealing with alphanumeric tail numbers; easier susceptible to conflict than air carrier flight numbers.
Airline callsigns are just as bad... in fact I saw a extract of an ASR earlier on today, that was filed for callsigns that were far too alike! Anyway... when a controller shortens a callsign then how am I to know he/she is calling me?