What you did should have worked.
You must have done something wrong.
There are 2 timers.
The short timer is 2 seconds.
The long timer is 10 seconds.
If a dialed number only matches "xx.", there will be a 10 second delay.This is considered an Indefinite Match because "xx." will match any number of digits and the long timer is used. The OBi doesn't know if you will enter additional digits, so it waits.
Adding rule "xxxxxxxxxx" will result in an Exact Match, but the dialed number can potentially match "xx." if more digits are entered. The OBi will use the short timer. "xxxxxxxxxx" is used because its a better match than "xx.".
Adding rule "xxxxxxxxxxS3" will override the short timer with a 3 second wait.
Replacing "xx." with "xxxxxxxxxx" will also result in an Exact Match. The 10 digit dialed number will not match any other rule with additional dialed digits, so timers are not used and the dialed number will be routed immediately.