Foam By Mail ("FBM") recommended against it, when I posed that query. The gal indicated it would interfere with the ventilation of the latex and thereby dampen a major benefit of shelling out the extra for latex, anyway. I presume this is due to a lack of the larger holes in the formation of the PU foam sections, that you can see on the latex pieces. So, I suppose if you like a warmer bed, that might not be such a big deal.
Of course, consider the source. They may just wanted to have increase their sales, now or in the future.
I have read claims of latex lasting longer than the regular foam, but the "HQ" foam at FBM advertises a pretty sufficient lifespan.
I was planning to do a regular foam base layer, but now I've decided to just order 1" latex layers from FBM and stack them until I'm satisfied. With free-shipping-on-$75, it's the most efficient thing I could figure out. I don't need the extra height from a regular-foam layer, anyway as I've bought a tall/storage bedframe.
Good luck,
Amy