Basically, what bimble says is correct.
But reading the rules won't help! If you value your sanity (or what's left of it) do NOT read on!
Rules of Shooting section 308 applicable to GNAS Imperial Rounds & GNAS Metric Rounds shot outdoors:
"...Where two or more rounds are shot on one day in succession at the same venue, only the first round will be accepted for a single round record, irrespective of bowstyle..."
The way I read this, in a tournament shooting 3 Warwick rounds in one day then the restriction would not apply if you shot rounds 1 and 3.
However this is further complicated by rule 304:
(k) An archer may only compete once, the first time of shooting, in any event regardless of the class of equipment used, the number of sessions in the event and whether the event extends over more than one day.
With GNAS rules, you need a good lawyer.
There are no such restriction on FITA rounds: just shoot what you like, when you like.
V