Which FICO score is being pulled for consideration?
 

Have an Amex and Citi. Both give me a free FICO score, yet the difference between the two is a whopping 100 points. Is one more accurate than the other?

The scale is different, and they likely were calculated on different dates, and they are based on data from different bureaus. Both issuers are displaying the score that they use.

American Express provides: FICO® Score 8 based on Experian data is the same score used by American Express....Your FICO® Score is a three-digit number calculated from the information on your credit report that falls within a 300-850 range.

Citi provides: Your FICO® Score is calculated based on data from Equifax using the FICO® Bankcard Score 8 model and is the same score we use, among other information, to manage your account. This model has a FICO® Score range from 250 through 900.

Does Chase pull a number more in line with Citi or Amex for anyone with accounts that get free scores. It would help determine whether or not I start applying with Chase now or wait a little while.

Amex pulls a FICO score based on general credit risk (max score 850). Citi pulls a version of the FICO score (max score 900) based on the risk associated with paying card bills specifically. It is 2 versions of the score and Amex likes to see the overall picture of a customer's risk whereas Citi's is more targetted towards the product they are offering.