He probably means the Favored in Guild Feat Benefit listed for Lodge Luminous (which is identical to the standard 5% discount from "psionic" type guild from DMG2).
On the bright side, Lodge Luminous from C.Psi has monthly dues of 25 gp per month and a one-time 100gp entry fee. Compared to the DMG2's 25 gp entry fee and monthly dues of 5 gp per character level, The Lodge Luminous would probably be much cheaper at higher levels (assuming you can't get Guildmaster as a bonus feat).
I was scratching my head at the 14.5%... I know I did the math in Excel (90% x 95%).
(I learned my lesson already thanks to your tutelage)
...I formatted the cells for percentage and had it round to zero decimal places...
I'm goofing off with a Disciple of Mammon fixer-type NPC for one of my campaigns, and I'm interested in your "Mundane Item Cost Reducers" section.
Would you consider adding the Apprentice and Favored in guild discounts there as well? I'd also suggest adding the benefit of crafting yourself (reduced to 33.33%)
For mundane items, perhaps only the 10% discount basic member Guild Benefit for subsidizing "the cost of goods, supplies, and guild-related services" might apply. (and even then, maybe only for mercantile guilds? I could see allowing arcane or psionic guilds to subsidize raw materials for mundane items that are intended to be made into magical or psionic items later... as that product will become new raw material for a magic/psionic item.)