Since first focal reticles have more glass to travel through to reach your eye aren't they more likely to be distorted by any issues with the lenses? I received my SWFA 5-20 and after adjusting the diopter the reticle never seemed quite sharp on max power. This was more so towards the outer third, but enough so to be distracting when first getting a sight picture. Sent it back thinking there might have been an issue with the diopter but the replacement is pretty much the same, which got me to thinking about this. Once you dial down below to about 18x or below it's not a problem, which is fine as I imagine most of my shooting will be around 16x or less. Is this a known trait of the FFP design, and is it an issue on the high end glass?