Slight Difference in Spoke Tension Between Inner and Outer Spokes on Straightpull Hubs?
Yes, it's normal and you correctly understand why. Some straight pull hubs can create more variance in bracing angle per side than a j-bend hub would. Other straight-pull designs (Velomax/Easton comes to mind) put the spokes in a straight line, creating the least of this variance possible.
On a j-bend hub, there is also some amount of this effect. But, it's usually very minor. How minor varies with flange thickness and rim diameter. In other words, it's at its least in a road wheel (big rim, dainty flanges) and greatest within BMX (little rim, sometimes thick flanges). You see the same thing where it's almost never a noticeable phenomenon building road wheels that the true optimal spoke length varies with the side of the flange, but if you look at nipple thread engagement on most BMX wheels the difference in engagement is readily observable. In almost any case with a j-bend hub, the effect is minimal enough and the rim is stiff enough that you can have all the spokes at the same tension and the wheel will still be visually true, because the rim stiffness is enough to make it that way. But, using a dial indicator on a very light, low spoke count rim built to near-perfect tension tolerance, you will be able to see the effect on the indicator.
Another way to think about it: the classical spoke length formula reduces the wheel to a bunch of circles and triangles between points in 3-dimensional space. It doesn't account for flange thickness unless you run the formula once for each side of the flange. It also doesn't account for the thickness of the spoke, i.e. the distance between its surface and center.
In practical terms, for bikes, once in a very great while, if you build a lot of BMX or ebike wheels, the whole thing can result in running out of threaded length on one side of a flange but not the other. I've seen it a few times. The importance of understanding this effect is actually in resurgence, because small wheel motor hub rebuilds are an increasingly common shop task, and they have some of the thickest, shortest spokes on the thickest flanges of pretty much any bike wheel genre in history.