Wow, very unusual spring packs. Not all the leaves taper on the ends. Some are square cut and thick, some are tapered. Looking at those pictures, the second leaf under the main is one they added. I can tell because it comes all the way up under and past the eye centerline. Factory springs did not do that. There are a few other odd replacement pieces in the pack as well. Maybe the other flat tipped ones were added to match the 2 units listed on the receipt. Factory leafs tapered in thickness towards the ends and had sliders between each leaf except for the bottom half leaf. You have an odd mix. The differences in ends, tips, and material thickness also means they will have an inconsistent rate
You could try removing the second leaf under the main and see what that does for you. Doesn't cost any money to try it.
When you stand on them, how much do they deflect? That is a quick rate assessment. Divide your weight by how much they deflect and you can approximate the rate. If you have an exceedingly high rate, you can give up some rate by removing a leaf and possible get a flatter installation as well. If you rate drops too much by removing the extra leaf, then you may want to get the whole thing de-arched.
Originally 318 cars have 4 leaves, so you've had it stepped up by going to 5 full plus the half leaf.
If their re-arch job was good, you may be able to dump the two added leaves and get were you want.
