No. All prices for additional guests that you configure on myfrontdesk will not reflect in a channel's extranet. The rate plan settings available in myfrontdesk are only for your mybooking engine and internal, first-party reservations.
The only rates sent to OTAs are those you designate in either the intervals of the Base Rates, calendar, or availability matrix.
To set additional guest prices for an OTA, you will need to do this in the channel's extranet. For more info about this process, please take a look at our article on How To Setup Distribution Channel Rate Plans.