Magus Spellstrike and Mythic Improved Critical (And other things)

So I was looking for information on making a character. I'm working on a level 16 Tiefling Magus, 2 mythic tier. I was looking at shocking grap shenanigans.
I have seen a couple builds that claim that Mythic Improved Critical increases the crit multiplier for spells used with spellstike to x3 up from x2.
When looking at the actual wording of spellstrike: "This attack uses the weapon's critical range (20, 19–20, or 18–20 and modified by the keen weapon property or similar effects), but the spell effect only deals ×2 damage on a successful critical hit, while the weapon damage uses its own critical modifier."
Does it work? If it does work can I get a full explanation of how? If not, did it ever work and is that why I keep seeing it?

The above is my main question. However, if there are some obscure magus tricks or builds that DO work within the pathfinder rules, I would greatly appreciate the quick info :D (please excuse the off topic note. I just figured it couldn't hurt to tack it on as an afterthought.)

Improved Critical does not increase the multiplier for spells cast with Spellstrike.

Spellstrike provides a specific exception that ignores the multiplier of the weapon used.

This works in the same manner as a magus using a pick: he would have a x4 multiplier on melee damage, but only a x2 multiplier for spells delivered via spellstrike.

Welcome to the reason 90% of magus builds use an 18-20x2 weapon.