[Dx-qsl] ARRL QSOs credit

[PY2YP]

I am comparing the DXCC band ARRL credited QSOs against my log, say: I 
have K7AJ credited on 40 meters in the ARRL record and in my log so this 
is OK, if I have W1AW as credited on 40 meters in my log I would change 
to K7AJ to match. However, I did notice that the ARRL changes the 
already credited QSO without any reasonable understanding. I've 4L, 
Georgia, credited on 40 meters for years but when comparing I saw 4L8A 
on 40 meters which I did work last year on RTTY; once this QSO was a new 
mode: digital, I submitted the QSO to the ARRL for proper credit on 
digital mode. The ARRL computer changed 4L7AA credited on 40m to 4L8A 
the most recent submitted on that band, despite of the credit was 
intended to digital mode. Of course this is not an issue, I can live 
with that after all but I wonder if there is any reason for that change? 
Does anyone also noticed this?
-- 
73 DX de PY2YP - Cesar