bradys555 said:

So APDS will pen more at range, but be less likely to hit ( WW2 )

Not necessarily.
The flatter trajectory of APDS does improve hit propability because it makes range finding errors less problematic. The increased deviation on the other hand does negatively impact hit propability. It depends on the situation.
The deviation problem has been solved during WW2 to a satisfying degree allready. But this was not implemented by all users.

APCR for example suffers more from cross winds. While in theory its deviation should be comparable to that of APCBC.

So there could be situations where APDS is effectively more accurate than APCR.

bradys555 said:

but the differences in pen at close and intermediate ranges would be negligible all things being equal.

That depends on how you define intermediate. Usually APDS allready outperforms APCR at the combat ranges common during WW2. (500-1000 m)

Is there some sort of link to a Range test that supports these findings, specifically about the angles of impact and penetration being more or less the same under similar  situations?

Well, there is data of tests of APCR and APDS.
But I don't know any comparisons of the same penetrator being used in APDS and APCR. Of course you can compare the test results of actually made and used ammo. But this will not give you the answers you are looking for as there are too many variables that differ.

There are also no reports from WW2 that suggest the behaviour you asked about in the amunition types used.

We know the penetration capability of APCR has been superiour to APCBC and APDS has been superiour to APCR. We also know that some early ADPS has had problems with deviation. Which where not severe enough to prevent its use though.
Everything suggests that APCR and APDS worked as intended and did so reliable. So both have been concidered an improvement over APCBC.
APDS was the generally superiour concept and was widely adopted after the war. Mostly replacing APCBC and APCR. The latter only remained for specific uses usually in medium or small caliber weapons.
Given the lack of any evidence or sugestion that you theorie is true there really is no other way than concidering it false. At least until evidence appears.

As a general comment I would add that its of little value to look at isolated statistics or performance data. Even if something like your theorie would be found during testing the question if it matters on a battlefield is an entirely different matter. There are simply to many variable and details different during each incident.

Ok, so in a nutshell the absence of any statements in any known references indicating that APCR was inferior to APDS in dealing with angled armor suggests it was not, or should not be by default considered inferior in that regard, because at it's (Literal) core it was essentially identical to APDS. 

Yes.