It's not that simple. You can be RNP-1 capable but not RNP-10 capable. This is because RNP-10 is used in the oceanic enviroment and the requirement is not so much for accuracy but for Nav without the assistance of groung based nav aids (VOR/DME).
The following is from the ICAO PBN Manual Vol 2
RNP-10:
Requires that aircraft operating in oceanic and remote areas be equipped with two independent Long Range Navigation Systems (LRNS) comprising an Inertial Navigation System (INS), an Inertial Reference System IRS/ Flight Mangement System (FMS) or a Global Navigation Satellite System (GNSS) with an integrity such that the navigation system does not provide an unacceptable probability of misleading information
RNP-1:
The following systems meet the accuracy, integrity and continuity requirements of these criteria.
a) Aircraft with E/TSO-C129a sensor (Class B or C), E/TSO-C145() and the requirements of E/TSOC115b FMS, installed for IFR use in accordance with FAA AC 20-130A.
b) Aircraft with E/TSO-C129a Class A1 or E/TSO-C146() equipment installed for IFR use in accordance with FAA AC 20-138 or AC 20-138A.
c) Aircraft with RNP capability certified or approved to equivalent standards
Volume II, Part C C-3-5 WORKING DRAFT 5.1 - FINAL
Anyone wanting a copy of the ICAO PBN (Performance Based Navigation) Manual which has all this info in it can PM their e-mail address and I'll pass it on in electronic format. It's a 1.28MB file