What are the success rate multipliers in SOS battles?

Question

This Bulbapedia article and this Smogon post say conflicting things about SOS mechanics.

If a call was made and unanswered in the previous turn, does the success rate increase 3 times or 4.5 times?
Does the super effective multiplier only take the previous one turn into consideration, or all earlier turns? Does it apply if the ally was hit by a super effective attack, survived, and was knocked out by something else? Is it a 2x multiplier or a 3x multiplier?
Are the answers different for SM and USM?

Please don't question my curiosity.

Comments

Bulbapedia and Smogon actually both say the same thing regarding your first question, but I can understand why you might have found Bulbapedia's wording confusing. The 1.5× multiplier for a call on the previous turn always occurs whether the call was answered or not; if it wasn't answered, an extra 3× multiplier occurs on top of that, or 4.5× in total, just as the Smogon post says.