fast_mttr_target value - what the db want?

i get a message that says fast_mttr_target need to be changed from 60 to 61. so I did it. now i'm getting the message that I need to increase it to 62.

the question is, how do I know the value the database actually want? I know the might be something going on internally that the db test everytime they are getting a new value and realize that it was not enough. but i hope there is a way I can find this value so I can do this just once, instead of altering this every day until the db no longer complain.