I think it is more that UF has different expectation for their artists and idols. They groom and expect their artists to be independent. That is basically what is happening with Bitter & Sweet. They have been forced to write their own songs and experiment with various way of performing, focusing more on live performance rather than single releasing. It makes sense in this era with low sale of actual music - performing live is the only way for an artist to survive. Bitter & Sweet has become very independent now. They have constant gigs at live houses and events and have their own weekly Showroom (internet) live. They do gigs in various forms including their normal set up, as a band with members from other bands supporting them or supporting other bands themselves, acoustic live, dinner show, and etc. They both have been learning to play other instruments. Asahi can now play a piano, a guitar and a drum, and Moemi plays a guitar in their live performance all the time now. It works for them because they both have strong drive to become "artists."
LoVendoЯ is a bit different because Reina was not really interested in doing a band in the first place, and I think Marin and Marina do have various interests like JonCC said. Plus, they get stable income and benefit being with UF as opposed to being freelances where you would have to sell your skills.
Up Up Girls and Ciao Bella are more like, matured, indy, idols in my opinion, so the management treat them differently groups in Hello! Project and UF artists.