Yes, I think it is due to the merger (SGS has extended the hours as well). Some club lounge folks told me the change was due to Marriott, but I was not sure if that was a corporate directive or because there are more Marriott people now working at more SPG properties in the ones I frequent and made decisions on a property level basis - I have seen extended hours at most other properties as well if I recall.
One of the nice things about Marriott, if you drink, seems to be longer lounge happy hour times, at least in Asia. I am staying at the JW Marriott in London next week. I am interested in seeing what Marriott is like there as it is my first time at a Marriott in Europe. Was not impressed with my US stays but have been pretty happy with my Asia ones.
But the laundry change was a bummer.