Blood Pressure Machines.

SO i was reading some post the other day about Blood Pressure. And since i have to renew my medical card next month i was curious so i went to the grocery store to test mine on the machine there... The results terrified me 161/100...Yikes!
I am 27 and eat healthy i eat about 1500-1600 calories and less then 1000mg of sodium a day, I don't smoke,I haven't darnk since College and i workout twice a day, an hour in the morning and an hour at night. I take low dose Aspirin, fish oil, calcium, vitamins A, B(complex) C,D and E and have never tested high for high BP...Ever!
So i went home with the intent of going to my Sister's house(who is in her first year of residency) the next morning to have her check it out, Because something was not adding up.
So my girlfriend and i went to bed, but i was to scared to sleep so my girl and i ended up going to Meijer's at 3 AM to buy a blood pressure monitor...An hour and a Half 3 monitors( Digital arm cuff, digital wrist, and the old fashion pump up kind) and $175 later i had learned that my BP was actually 123/84 and the next morning120/80 and again today 120/80(By my sister).
I did some research on the grocery store type monitors(why didn't I think about before the $175)...Turns out that they are rarely if ever recalibrate so they give a false reading. And also the cuff is to small for many people's arm, The directions for all of my monitors say that the cuff must cover 80% of your arm...Now i am no Sly Stallone but i do have larger arms then the average guy and it was a struggle to get my arm in the cuff at the grocery store. And i know it would be hard for a lot of people to do so. If they are going to but these machines in public places,they should make sure the vast majority can use them and they should also maintain them.
So any ways I thought my costly experience could be a helpful lesson to the people on this site...Hopefully!