The "Basic" class is 5 days....the classes typcially end on a Friday...and the ASNT Level III Basic test is offered on the following Saturday.

The Level III refresher classes are usually two or three days long.  For Level III MT, the classes are two days long, and are typically scheduled such that you can then take the Level III test on the following Saturday. 

You said, "Then i will be taking MT LVL III when im there, so for this, i will again be tested on the basics(all methods) but it will also fosus on MT in detail.  that gives me a LVL III in MT." 

You will not be "again tested on the basics".  Once you pass the Basic test, you are done with that.  The level III tests are only on the specific method,  (the magnetic particle Level III test is only on magnetic particle, no basic questions will be asked during that exam).  You need to pass both the Basic and the MT Level III to hold the level III in MT.  If you want to get another method certification, such as UT, you have to then take the level III test in UT, but you only have to pass the Basic test once.  Hope that helps.