Why DHCP assigns addresses from 192.168.88.254 to 192.168.88.2 and not from 192.168.88.2 to 192.168.88.254, when IP Poll is 192.168.88.2-192.168.88.254?
Why not? 
I think it was easy to program 254..253..252, etc for the programmer : P!
But.. what’s the problem with this?
It’s just habit. It can be simpler for me to use and configuration.
How I can change it or turn over?
Huge discussion about that already:
http://forum.mikrotik.com/t/dhcp-ip-pool-lease-in-reverse/48974/1
DHCP standart. We just follow it.
The standard is to go backwards? I don’t care that they go backwards, but I wouldn’t call it “standard”.
DHCP pool should be used only when it doe snot matter what actual IP client gets. If it doe smatter, then use pool for initial connection and then assign static IP to that client.
For example, if you have IP range 192.168.1.0/24, gateway is 192.168.1.1 and you want users to have ips from .2 to up, then set dhcp pool to range 192.168.1.250/192.168.1.254. When user gets IP from pool, make it static and change IP ti whatever addres you like, just not one that is listed in a pool.
Your comment does not having anything to do with the OP’s question, and I disagree with your statement. Read the other discussion. Some people want increasing order, some people want decreasing order, some people want random order, etc. Sometimes, order DOES matter.
Also, when you say that making static IP’s is the solution to making addresses go “from .2 and up”, that is crazy. You cannot give everyone a static IP address and then say problem solved, they go in order now. That would be an administrative nightmare!