How low bidding effects ad placement in Facebook?

[webapex]

I'm looking at sustaining an ad campaign, but a a lower pace so more different members get to see the ad before the campaign budget runs out (when I see the Frequency stat showing individuals have seen the ad 10 times, it seems like time to slow down the blast)

Having no explicit display frequency controls, I find lower bids help slow the impression rate of paid ads, and wonder how it effects the placement.

Presumably the ad position will be lower on the page, but will it also be shown on lower ad demand pages?. Perhaps that ad will only display for uses with few likes making for and fewer potential ad matches, which might be a good thing.

I guess there's no concrete way to determine the placement, other than making the ad match your profile page.

They seem good at throttling impression volume to make your budget last the whole day, at least for CPM.