In other words, in MD, there is essentially no Rule of Law, and everything depends on who you are, how much money you have, and whether or not some sticker on your car, the color of your skin, the size of your political contributions to the Governor's re-election campaign, or some random reading material on your back seat sets off the LEO who is looking to pin something on you...
With regards to the un-reciprocal reciprocity between MD and MI, there are MANY states who recognize MD permits--generally states with VERY freedom-loving gun laws (NC is another with one-way recognition). Some states think that if you qualify for a permit in one state, it should be good in EVERY state. The MD State Police (who issue MD permits) on the other hand, has actually stated in official testimony before the MD General Assembly that they consider all other LEAs to be so utterly incompetent in their investigative techniques, and so devoid of scruples in issuing permits, that they cannot be trusted under MD's "strict issuing policies". (which BTW, has no training requirement or range qualification requirements, but DOES have a "WWW" requirement--wealthy, white, and well-connected)
What that really means is that many states will issue permits to blacks, hispanics, women, poor people, and people who aren't politically connected, and in MD, the State has decided those are the "wrong kinds of people" to be carrying firearms.
On a more upbeat note:
FOPA transport rules DO apply in MD, regardless of what MD LEAs may believe. If you are truly transiting MD (meaning you are NOT making any long stops like to go shopping or attend an event, or stay overnight) you are PERFECTLY legal to transport a firearm through MD under FOPA rules--unloaded, locked up, with ammo in a separate container. (Magazines CAN be loaded, just not in the same container with the firearm). If you follow FOPA, you are 100% legal to transport a firearm THROUGH Maryland.
Now, if you get pulled over for some reason, and the LEO discovers you have a gun in your car, it will probably be seized, you will probably be detained, and if you even attempt to protest or cite Federal law in your own defense, you will probably be arrested, beaten and Tazed.
Because that's how they roll in MD.
My advice is that the ONLY way to be 100% safe in transporting a gun through MD is NOT to travel through MD with a gun. Go around this god-forsaken cess-pit of corruption and graft, and see the sights of 2A-friendly states like PA, WV and VA. A few more miles and a few more hours added on to your trip will be rewarded with beautiful landscape, friendly people, and the Freedom to carry your legally-owned firearm in whatever mode your permit allows.
One more pointer about traveling in MD--if you have any pro-2A stickers or Tea Party type stickers (like Gadsden Flags) on your vehicle, be advised that the MSP issued a training memo last year advising MD LEOs that such stickers/magnets were reason to exercise EXTREME caution during traffic stops, because the driver was probably an armed, belligerant illegal gun smuggler, bringing illegal guns into MD to sell to the gang-bangers in Baltimore and PG County. Really--you can't make this stuff up...
Good luck with your trip.