No, it doesn't. I think people who choose heat over chemicals retain more length usually tho. Why do I think this is? Well, chemicals are far more tricky because they react w/ a person's body chemistry. If someone takes X med or are having hormonal ups and downs (LOL...their period, to be precise), the chemicals can and will react differently. IOW, everytime a woman sits down to get a perm, the time it's left on may be too little or too much.
Heat is a lot less tricky, if you or the person doing it knows what they're doing and aren't going for a "bone straight" hard press.
I think retention for perms is usually less because the tendency of beauticians and their lients to seek bone straight overprocessed hair as well.