I've dived with CnG on 2 trips in the last 6 months for a total of around 30 dives and I don't recall any dive planning to 45mins, most of the dives were about 60 mins, give or take, and some of the muck dives went a bit longer than 1h. The only dives I remember that were significantly shorter than 1h were at Canyons and Verde when we had to fight some wicked currents, but the dive plan wasn't initially set up for 45min.
To be fair, there are other operators in the Philippines that are very generous with dive time where you can basically dive your air till 50bar (70-80 min dives with Alona Divers in Bohol) and then there the Thai liveaboards from Khao Lak that Centrals was referring to, where dives were really limited to a ridiculous 45min+5min safety stop, so CnG is somewhere in the middle, but I don't think it's fair to say they 'shortchange' wrt dive time. And they do try their best to divide groups based on experience/skills, although I guess it all depends on who else is diving on the day.