Difference between an equity account margin and a futures account margin

CFA Level I
#1

As per the title, is anybody able to explain the difference between the two?

My understanding is that for an equity account margin you only need to restore it to its maintenance margin. For example, if the stock price decreases, you have less margin to pay?

Whereas in a futures margin you need to restore the maintance margin to its initial level, regardless of the price of the future. So for example, if the future drops 80%, you will have to pay a margin which is greater than the value of the option?

Can someone please correct me and/or rephrase it please

#2

Is anyone able to explain in another way please?

#3

My understanding is the same as well.

In futures margin if you fall below the maintainence margin you need to come back up to the initial margin.

In equities once you fall below the maintainence margin you need to come back up to the maintainence margin.