alignment and tire issue

hi im looking for advice about a 2010 prius 4 bought on fathers day weekend 2010 . at the 15000 mile service the tires were rotated front to back after we got home about 45 minutes. my wife noticed a noise frist it sounded like a flat spot on a tire some pavement it was more noticeable. we called the service dept .
here goes the routine they said i would have to contact the tire mf. being goodyear fuel max 195 65 15 these came on the car and at the time was averaging abt 44 to46 mpg
i took it to our local goodyear they said theywerent a factory store and didnt like to fool with those issues because or slow payment
i call toyota and talkto service mgr he reluctantly looks up a number
i call goodyear they gave me the same goodyear i had talked to
i said they didnt want to look at it the lady calls them they say ok
i take it in they put it on the rack the service person says the fronts rotated to the rear are flat spotted the drivers side ruined the passenger side not far behind because the front end is out of line
i call toyota service make app take the car in
service dept checks it out in a few minutes they tell me they will put us on a new set of yokohamas no hassle
i ask are they equil to orgional they say yes p195/65/r15 avid trs
i ask was it out of line they say no abt a2 hr. wait they say almost done lining it up that sounds strange
on the way home noticed mpgs there down way from44 46 to as low as 35.6
we have drove abt 800 miles on this set
today sunday 5 15 2011 drove abt 120 miles one way max mpgs were 37.8 at best
coming home 120 miles aired the tires to 40 psi allway round to see what would happen 40.6 mpgsand thats at best
i suspect these arent the fuel saver tires but cheaper ones when i checked the psi after install it was 31.5 all 4
as bad as i hate to im gona have to call them monday and complain
man what along drawn out bunch of crap im so dissapointed in this dealer and situation now i think there all the same. does any one have any ideas on this yokohama avid trz is it a correct fuel saver tire?

 

its 12:57 and bed time but i think ive found an answer checking the two dirrerent tire specs even though both tires are the same size the yokohama weighs 21#s and turns 831 revs per mile so this will make the speedo slow
the goodyear fuel max weighs 19#s and turns 836 revs per mile that came on the prius orgionally
at least thats the way i understand it on tire racks web site

 

thanks for the input this tire thing seems to be a guessing game at best. the dealer admits the goodyear integerity fuel max is problem prone tire at best . i thought they were assurant fuel maxs but they were the integerys ,specs are the same all but tread wear its less i take the prius back thursday for them to look at it .dont know how its gona turn out .fueled up checked mileage with pencil 39 mpgs interstate with cruse on down from 44 46 mpgs