I don't understand sentai.
Their release of Prisma Illya season 1 is missing the 5 specials (the first one being the debut of Illya's beast mode outfit)
They released the 1st OVA (the gym outfit school dance)
Next with 2wei they didn't include special 2 which is about Miyu asking Luvia about bras and panties and special 4 which has Illya/Miyu/Kuro and Illya's school friends trying to attract customers to a restaurant while wearing china dresses.
Don't know why special 2 was omitted when special 1 is basically about the same thing but with Illya, Kuro and Sella. With special 4 maybe sentai was afraid of showing Kuro being seductive which is dumb because...
Their 2wei Herz release includes all of the specials which means they dubbed Beast Mode Kuro being horny for Miyu.
One guess on why they didn't dare bring the 2wei OVA over here (they could've released it under Critical Mass/kitty media and gotten away with it I bet, not a lot but some loli h-anime [or h-anime with loli scenes intact] were brought to the states)
Apparently sentai lost the license when 3rei came out but released the Oath Under Snow movie later (last I skimmed it has only one panty shot for Miyu) and Prisma Phantasm which only has a small bit of fanservice from some new glasses girl who isn't a loli so I don't care, both are sub only.
And when I checked sentai's site they aren't selling 2wei Herz anymore (other listings are jacked up in price now), could be distribution issues (since Herz is on HiDive but not the OVAs) but the pessimist in me wants to say they got in trouble or decided to stop selling it to avoid bs law issues.