Created shipment using the single SKU pallet template, Amazons till allowing me to ship Small Parcel (UPS)????

Hello everyone. I have a question regarding small parcel shipping and using a Single SKU pallet packaging template.
I am shipping inventory into FBA. I have selected a single SKU pallet packaging template for this inventory. As I progress in the shipment creation process Amazon allows me to ship via Small Parcel. SP is cheaper AND since I created a single SKU pallet template Amazon is routing the shipment to a single warehouse. I can download the Small Parcel labels without issue. Theoretically I can simple slap them on my boxes and hand them over to UPS.
**Question: Did I just find a single warehouse routing hack or something? Or would sending a Small parcel shipment using a single SKU pallet configuration be an issue somehow, and I should be sending this shipment using case pack configuration instead (doing this splits the shipment into 3 shipments with seperate destinations)
I cant imagine why Amazon even allows SP as an option if you select a single SKU pallet as the packaging template. But they do, and I would like to send it this way as it cuts down on destinations.