It's a bit more complicated but the short answer is yes... sort of.

The long answer is that with PPLNS sometimes your payout may be well below the 100% PPS equivalent and other times it may be well above (due to variance).  If you switch over to WestHash when the payouts are going to be averaging well below BTC/TH/day then you benefit.  If you switch when your payouts are going to be well above then you lose out on the higher PPLNS payouts.  Since you can't predict the future then you don't know in advance when those good times will be coming.  In theory the good switches and bad switches should average out thus allowing you to switch at a lower value (e.g. 0.0109) and benefit in the long run (just as with a PPS pool).  This assumes that both pools can be treated as closed systems with no other interaction (more on that in a moment).  In practice they didn't average out for me and I lost BTC0.19 before I accepted that others were right to recommend a higher threshold than I used.

About closed systems-- I can't prove this has a significant effect (I only have 4 weeks of data doing PPLNS alongside WestHash-- which is way to short to make conclusions from), but my intuition says that you can't quite treat the two pools as completely closed systems.  The reason is that there are times when WestHash's rental rate is low enough and this pool is also having a block drought that other miners will decide to rent with a fixed rate from WestHash to mine here.   That alone isn't enough to switch over your miners, but if WestHash has a rush on some altcoin while those rentals are busy mining here then it might result in an increased rental rate high enough to pull your miners off this pool just as a bunch of TH is being tossed here to bust the block.  It could start raining blocks here just a couple days after you have most of your attention over there.  At least, that is what happened to me on multiple occasions when I had the p= set too low.  Can I prove this interaction actually is significant and not just anecdotal-- no, I can't.  It is up for debate how much the rental mining here increases the rate on the later altcoin mining at WestHash (the switch may have been inevitable anyway).  Still, this interference means that there is more going on than simple averages and thus it's "complicated."  There is potential for bias toward missing the better payouts here... or maybe not.  I can't tell for certain, but it didn't look pretty when I ran my own numbers for a lower p=.  I figure that by using a higher p= that it makes the (possible) issue mostly irrelevant.  I would much rather ride the variance here than risk losing the rewards here because I was chasing a rental for some altcoin of questionable benefit over there.

I'm actually considering bumping it up even more than 0.0115 or just breaking the habit.  Profit switching with PPLNS just doesn't seem to be worth it compared to doing so with PPS, but I don't care for the PPS pools out there right now so I keep my miners here.