Stacking Personal Upgrades

[Garbage-Tier Waifu]

So, a few people I was talking to noticed, along with myself, that personal upgrades do not explicitly prevent you from having each model boost the same ability score, as they are untyped bonuses, and there is no restrictions as we can see in the rules (thus far) that suggests that untyped bonuses from the same source do not stack (if personal upgrades are consider the same source). So, is there anything preventing personal upgrades increasing the same ability score?

(Also, as an aside, is it possible for a rules forum section to be added to the Starfinder section? I feel that since the PDF is in peoples hands, we should have a section dedicated to discussing rules questions.)

[Colette Brunel]

It seems that the book failed to take into account Owen K.C. Stephens' word here on stacking personal upgrades here: http://paizo.com/paizo/blog/v5748dyo5ljwx?Cybernetics-and-Augmentations#14

[Rysky the Dark Solarion]

Just read over the Personal Upgrades section and while it doesn't explicitly say you can't do it it very heavy implies you can't by stating to keep an eye on what abilities you have upgraded and that you can improve an individual upgrade to the next tier.

[DM_aka_Dudemeister]

As far as I can tell you can't put multiple models on the same stat. The only way to improve a single stat is to upgrade from either +2 to +4, or +4 to +6. You can't improve via personal upgrades beyond +6.