I have had D'A sets where the wrong string was in the packet. I measured them with my micrometer and sent pix to D'A customer service, who promptly sent me a few of the correct gauge. And yes, on a traditional set of bass strings, the D is usually a greater diameter than the math might indicate for a "balanced" set, because of way back when Fender's bass necks had a more pronounced crown radius. The D string was made thicker, meaning more mass, so it would have the same relative output on the original single coil pickup. Output varies as the square of the distance of the string from the top of the pickup, not linearly. So a little bit goes a long way and drops off quickly when the string is further from the top of the pickup. So your observation is normal. If you want a more balanced set tension-wise, use the D'A 170BT. This is the set I gig with, for that very reason: more even feel across the strings. With flatter fingerboards, the need to thicken up the D string is not necessary anymore. Finally, because of something about the D'A formula with the comparative diameters of core and wrap, I have also noticed over the decades that D'A strings have comparatively slightly less tension than equivalent diameter strings of other manufacturers, at least for their XL NPS strings.