Rate limit of ppp profiles formula

hello;

i have mikrotik server installed on rb 450g ,i saw in ppp>>>profiles>>>rate limit

the following equation " formula" which is in the red rectangular,as shown below





what i can under stand is 400k is the first rate the client receive for rx & tx

after some time the rate will decrease to 250k for rx & tx and still to this limit for 8 sec

after that the rate will be fixed to 300k for rx & tx.

this is what i think, but what the benefit of the other numbers i do not know ,and am not sure how much correct what i said above about the formula and how it work.

if there is anyone can explain to me what the formula mean & how it work exactly i will be grateful.


my best regards.