Thanks sebastia!
It WORKS wonderfully! (tested for 4 days)
I had to use this script for the qos http://forum.mikrotik.com/t/fasttrack-friendly-qos-script/102401/1 even if I had to run it in blocks (I don’t know how to find the error in the original script I think of a syntax error but I can’t correct it)
P.S.
Is it possible, to automatically vary the MaxLimit to the external interface? (My ISP lowers the upload in peak hours from 3M to 2M)