Advise for a newbie please.

Pricing an itinerary which involves premium economy fare on ITA Fare Matrix. When copied into BWM, it returns “book with Flight Network” and a fare 227 euro less than ITA Fare Matrix.

Is book with Flight Network just an economy fare instead of premium economy? Or is one of the taxes or fees (YR? :-) not priced in the fare?

Apologies if this is a newbie question which has been asked and answered multiple times.

Not sure how to paste a screenshot but in ITA Fare Matrix but am entering on the round trip tab:

Depart from: AMS

Outbound routing codes: LHR PHL

Outbound extension codes: F bc=p

Destination: LAX

Outbound routing codes in reverse PHL LHR

And same Outbound extension code

Outbound date 04/17/2019

Return date 04/29/2019

No other options selected.

ITA Fare Matrix: 946.48 EUR

BWM Book with Flight Network: 719.37 EUR

Thanks in advance for any insight.