Whenever I use only str8s for a while, I have a problem with nicking myself when I go back to a DE. You get used to and don't notice the pressure with a str8, but it suddenly gets you when you pick the DE. Once I adjust, it's fine.
You use pressure with a straight? I'd have thought that you'd need more pressure with a DE, as there is so much more metal lying against your skin. With a straight, the only thing in contact with your skin is that impossibly small area of metal along the edge. For this reason I use no pressure, pressure is what gets you cut.
When I was first using the straights I found in antique shops, I used a little pressure, and needed it to get a good shave (still, it was less than I used with the cartridges). When I learned to hone, they all became a lot sharper, I cut myslef a couple of times, and soon learned to back off on the pressure. For me, when I find myself starting to press a little harder, that's when I need to hone that blade. I put it down and take up another, if I still have a fair bit of face left to shave.
I used the DE with the same zero pressure, still nicked myself, and didn't get a close shave. As you say, it's a different technique.