107 K plus miles, up-to-date servicing, new tires but now low MPG

Our previously perfect Prius is now experiencing mushy steering, serious loss of MPG. It was 52, now it is 47! It has all new tires, replaced last week, with alignment. Previously, the right rear tire was out of alignment to the point where it wore that tire out. Rather than have one new tire, we replaced them all, about 8 thousand miles early for this set of tires. All fluids have been checked and oil changes with synthetic done on time. No problems of any kind have been reported to us by Luscious Garage. The tires are at 35 pounds in each. Does that seem right? I was thinking it should be much higher? We now have ecopia tires, which we've never had before. By the way, this is a Touring, so it has the larger tire and even so has always had great MPG at 52.

 

okay, we will increase the air pressure and wait a while. I thought 35 sounded way too low. I heard this over the phone from husband who leaves all car work to me. I'm getting some kind of cold and don't like to hear of any issues with this perfect car. Just read about the guy who actually traded his car in on a different one, because at 110,000 he had a bad traction battery. It seems to me that he could have tried other approaches, and I plan to be in this for the long haul. Its just that my husband is used to the car being absolutely perfect.