To clarify, EI is offering the fare you want for $890 and the Chase Travel Portal is showing $1126 and the corresponding points to cover that charge?
Ideally the CTP would show you the $890 fare and you'd use points at the 1.25cpp bonus rate for having the CSP. The CTP is run by Expedia and if Expedia isn't offering that fare, and in some instances even if it is offering it on Expedia.com, you won't be able to purchase it on the Portal.