I researched this a bit, and I found that WordAds are currently displayed once at the top of pages, including a home page using infinite scrolling. Note that may not always stay the same and the WordAds team may update that in the future. Also, I appreciate that you've posted a good explanation about why you want to make a change like this.
To switch from the Load More Posts button to older/newer links in the Enterprise theme, add this to your Appearance → Custom Design → CSS editor:
#content .navlink {
display: block;
}
#infinite-handle {
display: none;
}
It would be cool if you report back whether it has any effect on your ads. I'd be interested in passing feedback like that along to our developers for review.