Ok! Lets try again...
Map 1 is base map for when not using meth.
Map 4 is when using meth.
That's what you need to know.
Now, when you select map 4, it actually use map 1 (base map) and when meth flow is detected it gradually switch to map 2 proportionally to flow.
So select either 1 or 4.
If you use 2 directly, you are using boost and ignition advance intended for use while meth flow, but without the protection of reverting back to map1 in case meth flow stops for any reason (empty tank, injector/flow sensor failure, leak...). When using map 4 it auto switch from 1 and 2.