Can someone clarify me on something with the Jargonaut build?

[Magpied]

Here is the guide.

https://www.dropbox.com/s/g196mx15afictws/Jargonaut.pdf

The guide advocates having your CHA as only 14 for this build and recommends all points go into strength. Wouldn't this build be unable to cast spells above level 4? Perhaps I don't understand the interaction with ability score and words of power, but I thought the rule was: you can only cast a spell of a certain level if your ability score is equal to "spell level +10."

I'd like some clarification please.

[SaddestPanda]

Basically, the guide is relying on a stat boosting item in order to cast the higher level spells.