Nah actually it differs a bit like JEE is a exam which goes in depth and Mht cet isn't that difficult depth exam. So many a times it has been observed that people who score well in JEE mains and fail to crack JEE advance also fail to score well in Mht cet exam, just because the studying pattern for both is different. So I'll personally suggest you to focus on only one. But yes while doing boards you will also be covering Mht cet.

Thankyou.