That's why it is more commonly referred to as the 24-in-7 rule, and not
"1 n 7", as the [old] rules say you have to have 24 consecutive hours free from duty and the opportunity for duty should the occasion arise - within every 7 days. Therefore, that rule does not provide for a full calendar day off... although that would provide for more rest.
The new FAR 117 rules (pax carriers) are even more specific and restrictive (30 in every 168 hours), and hopefully - one day - it will apply to the cargo carriers as well... as it should. Sorry about that...