I think its the problem araised due to the interdigit timeout since the destination pattern is specifed .T.
Trying dialing the same number and last use a # as terminator. If you see difference in delay its due to interdigit timeout.
There are situations where expected dial-strings do not have a set number of digits. In such cases, Cisco recommends you configure the "T" terminator on the dial peer destination-pattern command in order to.use variable-length dial-peers.
The 'T' terminator forces the router or gateway to wait until the full dial-string is received. In order to achieve this, the 'T' terminator forces the router or gateway to wait until the full dial-string is received. The router or gateway:
Waits for a set interdigit timeout before the device routes the call.
Routes the call once the device receives the "#" termination character in the dial-string. For example, if you dialed "5551212#", the "#" indicates to the router that you dialed all the digits and that all digits prior to the "#" should be used to match a dial peer.
http://www.cisco.com/en/US/tech/tk652/tk90/technologies_tech_note09186a008010fed1.shtml#topic7
