Ever since last winter, I've noticed that they haven't been able to accommodate any 4pm check-outs (even for Platinums). And, I stay at this hotel very often too.
During the ski season, it does get quite busy (understandably so) and housekeeping needs to get the rooms ready for the mass-return from the slopes. I didn't think that they wouldn't be able to extend this during non-busy times.
Also, during the ski season, upgrades are usually not granted either. You're very lucky to get a 1-bedroom suite. I usually have to pay for mine (even as Platinum).
Btw, what day of the week did you stay? Was it busy?