Why are hydraulic roller lifters, different on different sides in the engines?

I find it rather strange that nobody else has overhauled a hydraulic-roller-lifter-equipped small block here in this forum & discovered the same as me & found out the reasons?
But most I wonder why they have different hard springs?
Isn't there anywhere to find out?
I mean that maby there's someone somewhere who's into it at least a wee bit...?
Please... purdy pleeze...?
(I wanna burn some rubber!)