You're never going to be promised verbally, or in writing, 100% of the advertised "up to" speed.
You can see what I went through back in 2010 here: »[WA] 10%+ Packet Loss in Kitsap
This problem is no where near as bad, but it's still up there. The other night I actually used my AT&T "4G" (not LTE, but somehow they get to market it that way) cell connection for media since the Wave connection was so bad.--
flickr | 'Cause I've been waiting, all my life just waiting
For you to shine, shine your light on me