IPs might be easier on CCX, but MIF gets harder...
If by "CCX" you are referring to the instrument flights I4202, I4203, I4204 & I4390 along with the visual nav flights N4001 & N4002, then yes, you can expect your NSS to come down from any previous projection. I flew these flights on my cross country, got fine grades, and mine still dropped a couple points.
Basis for my generalization? The MIF for the I42xx and I4390 flights is very high. On my I4390, for example, I had zero 3's, thirteen 4's and five 5's for a cumulative score of [77] and so only beat MIF [71] on the flight by a ratio of 1.085. (My understanding is that a cumulative ratio of 1.15 equates ROUGHLY to an NSS of about 52.) Therefore, I would've needed TEN 5's and EIGHT 4's just to average 1.15 on the flight. Not impossible, I'm sure, but I'm definitely not that smooth.
That said, since MIF on the N4001 & N4002 VNAV flights is relatively low, so if you flew VNAV -- or better yet, VNAV AND Night NAV -- on your CCX, you might make some money. Or, if you're an instrument all-star pulling more 5's than 4's, then please disregard my ramblings and accept my humble congratulations...
Lastly, for everyone else waiting to jump in with the "quit worrying about grades" lecture, save your keystrokes. I'll be the first to advocate simply working as hard as possible in Primary (particularly in early-stage sims and flights where MIF is low), but you gotta throw some food for thought at the guy who's complete and sitting around waiting for the Gods to decide his fate!