I also join a plan in THE SPA similiar to the one you mentioned. Mine limited to 2 machines only. I go as the sales lady suggested, 3 times a week, 2 parts of each machine each time, each part means 30mins works on any part of your body as you wanted. With my committted participation in 3 continuous months, my weight and shape has not change at all. Even the sales lady doesn't understand why these machines have no effect on me (my diet is normal and occasionally eat pure veggie salad only). O, a little background of myself for your consideration, I used to be a medium size lady before 1st pregnancy (110lbs, 160cm/5'3" tall), tried M6 before wedding and lost about 10lbs with firmer muscles (which means machine shall work for me). So, hope with my experience can help you consider puchasing such package!
If this is the case, I may not join The Spa lar. Although the package price is not very expensive but if it doesn't work or difficult to book, it is a big problem!
I may join another 美容院 in CWB suggested by another BK mum.