Pakl said:
Multipliers are official from SEG
Which doesn't matter if the plot's events don't support them. Guidebooks are meant to supplement the original work, not take precedent. Trunks stated Post-Rosat Base Gotenks should be able to fight evenly with Boo based on his showings prior, with Piccolo even seeming in agreement, yet a 50+x gap between Post-Rosat SSJ Gotenks and SS3 Goku is never implied at all. Gero's calculations also don't work at all if treating the SSJ multiplier as a static 50x at that point of the series and if the deciding factor of placing pre-Rosat Base Gotenks so low is something as arbitrary as multipliers when all supporting evidence in-series point to him being SS2 tier, then you're left with either admitting his SSJ multiplier isn't 50x or making the gap between SS2 and SS3 a 50x one or so, and one option is obviously far less ridiculous than the other.
Besides, Toriyama stated himself he initially envisioned SSJ as a 10x boost before the inflation he'd gave Kaioken prevented that during the Freeza Arc, and official material such as the Dragon Ball Super manga present the gap between SSJ and SSB as being little more than a 10x one, whereas the former Goku's performance against Initial Hit wasn't a completely different league from what he accomplished in base. We also have Rild implying that by the time of GT, the SSJ multiplier was little more than a 2x boost.
Yes, I can already hear you typing "Hurr durr, GT and Super aren't the same as the manga!" Well, guess what? Neither is a secondary, supplementary source, especially when one of the most notable ones (The Daizenshuu) covers both canon and non-canon information and is far from an infallible source.