With register reward deals you can only get 1 RR for an item per transaction..lets say crest toothpaste.. if it is in the ad for $2.00 and get $2.00 in RR and you have a q for $1.00 ( btw this is NOT a real deal just an example) so you want to get 5 toothpaste. In order to get the RR for all 5 they have to be done in separate transactions to get all 5 $2 rr. Another reason people do more than one transactions is to roll the RR. They will start their trip with one transaction and get $10 in P&G RR then transaction 2 is full of unilever products so they pay transaction 2 with transaction 1 RR and still get the RR from trans 2 since it is a different manufacturer. It does pay to know your manufacturer products !
oh.. if using coupons and RR please know you need more products than coupons ( RR count as coupons) so you may need fillers so if you find super cheap candy or pencils 10/$1 or something cheap pick some of those up to add to your transaction so you have more items than coupons.