A bit of an oversimplification. When you have somebody like Dr. Rudnick on your staff, somebody with decades of experience working formulation, testing, and development, this is somebody who knows what they can tweak in an approved additive package to improve performance further, without causing issues with other aspects of the product's performance. When you aren't constrained by cost, one may be inclined to, besides using better base oils, increase concentrations of certain additives that you know are complimentary or can improve AW performance, within a given targeted area of applicability (the applications this lube is designed for).
So, take the oil I have on-hand, it's based on your typical full-SAPS Euro-style lube. This is when additive packages weren't being manipulated for LSPI compliance, because that wasn't an issue with these "heavy handed" formulations. This was due to the high levels of ZDDP, which is an LSPI mitigator. So, this oil, if you are making formulation changes to it, you know your target audience; what applications this oil is geared toward, so you have a good idea as to what you can manipulate to improve it (again, no budget consciousness being entertained here) where you think it can be improved. Then you can bench test parts of this, and then field test others, to verify.
If the oil in question is one based on an SP/GF-6 style additive package, the approach may be completely different, because with these oils, LSPI mitigation has to be considered as it was when that additive package was developed. Calcium concentration becomes an issue for example. Are you going to increase ZDDP beyond baseline to account for other formulation changes you are making or are you going to keep this at spec level? This will have an impact on what you can change. Also, what are the expectations for this product in the field? Is it going to be used in cars that might use considerable oil where catalyst protection (or GPF protection) may be important?
Now, if you are running one of the HDEO-style additive package oils in a gasser application, with the higher levels of AW additives right out of the gate (like Wayne), that changes things again. If you are doing this in a turbo DI engine (which Wayne is not, it's in a port-injected DOHC FCA mill), which one would assume this oil isn't designed for, nor its foundational additive package tested against, that's a whole other kettle of fish. It's also not really within the scope of Zee's query about how development and materials selection followed by testing progresses.
There's so much further we could go down this rabbit hole too. I suspect that the Euro lubes, at least the full-SAPS ones, could likely be submitted and approved for A40, 502/505, 229.5...etc. There's not much you can do to those formulations to make them non-compliant, you'd have to make the product perform worse, which clearly isn't the goal.
On the other hand, with many of the more recent approvals, when you start getting into SA limits, ZDDP limits...etc, well, some of the changes that improve performance scuttle compliance.