The money would be better spent for 20 Ospreys for use on the QE class carriers to go with the 35's. They would provide a credible assault, air to air refueling, covert ops, cod, etc capability and you would still have $1.5B left for support and mod to an EWA config.
In today's world ship based helicopters make for a sitting duck if you have to go up against a contender.
The Sultan