The following information has come from my sister (someone who hates Dragon Ball):
SS4: Saiyan goes Golden Great Ape (Super Saiyan Great Ape) but gain controll of themself
SS C-Type: Wrath State (Great Ape Power) + Super Saiyan
This means that SS4 & SS C-Type are equal in power.
LSS is SS C-Type at max power.
SS4 has a max power state.
All in all, my sister summed it up to that SS4 isn't cannon because it is too dang strong! think about it:
SSB Kioken Vegito couldn't fight Cumber, as in Cumber wasn't phased at all. But SS4 Vegito defeated him with ease! We all know that Cumber is stronger than Broly because he (Cumber) can take on a SSB Goku without tranforming of anything while BRoly had to go Stage 2 Wrath State.