Check the height of the handlebars. The head tube length is 105 on the Jamis , and 150 on the Specialized. If the difference in handle bar height is also 45 mm (1.8 in) it could be that you are able to get more support with your arms on the Specialized.
Here are two other thoughts on making it easier to step down on a pedal in the power start position:
1) To echo DarthLefty's comment, it might help to drop down a gear or two on the cassette. That way there isn't as much resistance when starting.
2) It might help to put the pedal in the 3 or 4 o'clock position rather than the 1 or 2 o'clock position. That way you don't have to step up as far to get rolling on the bike. A shorter step up might also be the case if the BB was really lower on the Specialized.
Last edited by Recycle; 12-04-13 at 01:38 PM.
Reason: tried to clarifytwo sentences