I'll guess that your Stations mailer was cut if you won "too much". You're going to find this at other casinos too.
My Stations mailer has stayed the same, but I play very little - just enough to get what's probably the lowest mailer of $5 twice a month.
I noticed that the Senior program is changing starting in January. Now called "My Generation Wednesdays". The January benefits are
half point dining in cafes and steakhouses
hot seat slots
free Starbucks
bingo bonus
Mexican specials
$4 movie matinees
half point bowling
free slot tournaments
Previously senior Wednesdays included half point dining at the buffets. Apparently they are not offering this - at least in January.