There are a few things a play when tempering chocolate, which nobody seems to mention in their online instructions:
1. The thermocouple on your ACMC is NOT 100 percent accurate. I have seen them out as far as 4 degrees.
2. Humidity is going to play a factor in the crystalization of your chocolate. Dry days it flows great. Wet days it's like working with tar.
3. The entire time you are working with your chocolate it is trying to form crystals. You can control the fluidity (viscosity) of your chocolate simply by raising and lowering the temperature while you are working with it one or two degrees at a time. Inexperienced chocolatiers will add cocoa butter to their tempered chocolate when it gets too thick. This only compounds the problem they are trying to solve, and mutes the taste. When your chocolate thickens, raise the temp of your ACMC a degree and wait a bit. If it's still too thick, raise it up one more and wait a bit. Once the fluidity is more manageable do a temper test. You'll quickly find your threshold for working temperature, and will never look back.
Just remember: Chocolate works at IT'S pace - not yours. Be patient. Pay attention to detail, and in no time you too will be a Kung Fu Temper Master!