RV7 firewall

Good day Guys.
I have a question regarding the firewall on a RV7. The plans say to draw a c/l on the bottom flange of the aluminum angle and to line that up with the second row of holes in the bottom skin. Done that, now it says to adjust the firewall so that the forward flange of the firewall is 5/8 inch aft of the side skins. Done that too. But when I measure the forward flange of the firewall to the BOTTOM skin ,it is slightly more than 5/8 inch, about 1/16 of an inch more aft. Is this normal ? Or should the bottom of firewall be 5/8 of an inch aft of the bottom skin. If I do that the c/l do not line up with the second row of holes any more.
Regards
Arie

I just measured again and the forward face of the firewall is 27/32 inch aft of the bottom skin. In other words it is 1/32 inch more than 5/8 inch. This is with the forward face of the firewall exactly 5/8 inch aft of the side skins, from top to bottom , on both sides. I am satisfied that the firewall is perfectly parallel to the side skins ,and at the corect distance, I just dont understand that the bottom can be out by 1/32 inch ,if the sides are correct ,and the center line on the aluminum angle on the back of the firewall lines up perfectly with the second row of holes in the bottom skin. Maybe it is supposed to be this way.

Firewall distance to skins

This problem can be solved by centering the second row of rivets on the part of the angle to the rear of its forward flange. In other words draw the line on the angle 5/16? forward of the rear of the angle (instead of 3/8?). This puts the rear face of the firewall exactly 5/8? from the front of the side and bottom skins and also gives exactly 3/4? clearance for the Longerons.