Is this normal?

Made it through yoga class #2.  I feel incredible.  Well, and I scheduled a massage for the afternoon.  Always a bonus.
First, though, I went into work and did some paperwork.  Short, sweet and still able to make it to my prearranged massage.  And, they called me to let me know that if I still wanted the 80 minute massage, they would be able to do it.  My therapist's appointment after mine, canceled, which freed her up.
Excellent.  Even better.  I arrive, use the facility, and wait.  She ushers me back to the room at 4 and inquiries about my reasons for having a massage.  Did I only want to relax?  Were my quads tight?  Did I prefer her finishing with my ears/face?  General questions that would enable a positive experience for me.  In the past, at this studio, I have had issues with some of the therapists.  I waiver, back and forth, with whether or not it is worth the frustration to have a membership to this business.
Still, I have continued, because I am too lazy to find a new therapist.  I like Brittney, I do.  Today, though, after scheduling an 80 minute massage which means I would be finishing the massage at 5:20, I was irritated when she finished at 5:09. I know because I looked at my cell phone.  In the past, I have had a 55 minute massage that finishes 5 minutes early.  I guess I had it in the back of my head that time would be a factor.  And, it was.  Immediately, I am annoyed and so I know it was reflected in my demeanor.  I tipped Brittney and made my way to the desk.  I owed more money since I had upgraded to an 80, I mean, 70 minute massage.  I paid thirty extra dollars for fifteen minutes.  That is what is super annoying to me.  I don't mind paying for services rendered but I expect the full amount of promised time.
Am I being ridiculous?  Is this customary?  To offer a massage for 60 minutes and cut out at 55?  Or 80 minutes and receive 70?  I am seriously considering cutting my ties with this studio as it is the only place that, consistently, I am jipped on my time.  I think I have two or three massages stockpiled.  I guess this will be a nice month for massages.  If you have suggestions of therapists/studios, in the valley, let me know.