Thank you for your interest in Graft project! To answer your question - Bitcoin transaction allows multiple outputs, i.e. you can send funds to multiple people in the same Tx. Standard Graft transactions such as Sale or Transfer only allow one to one payments. I agree that this is not very clear from the description; "standard restricted number of recipients" would be more precise definition than just "size". Anyway, this is not big deal but this is just one of several measures to control the number of free transactions to prevent bloat and DOS.