4ad is stacked with m1t to give your body exogenous testosterone, which boosts libido & helps with lethargy which are strong side effects of M1t. M1,4ADD coneverts to dbol, it would not provide any of the same benefits as 4ad. It's a good compound, just not good to stack with m1t.
I would not advise anyone to stack methyls. You could run a 4-week cycle with 2 weeks m1t & 2 weeks M1,4 ADD.