MXR Phase 90 Differences

Alright, what's the C11 and C12? And why doesn't R28 change everything? Check it out:

A vintage script logo Phase 90:

Notice it corresponds exactly with the schematic at GEO, except for the feedback resistor. We have six .05u caps, two .01u caps, and two 10u caps.

A vintage block logo Phase 90 with a script logo board (single opamps):

This one is almost exactly the same as the one above, six .05u caps (two film), two .01u caps, two 10u caps. FET resistors are 24k, and a 24k feedback resistor added. The LFO resistor is 4.7k, but that's not a huge deal.

Now we have a vintage block logo with a block logo board (dual opamps):

Lots of changes, more than just R28! There appears to be six .05u caps and two 10u (or one 10u and one larger) caps, but there's an extra .01u cap and a 680pf (I assume) cap. Those two are probably the C11 and C12 caps. There are a bunch of other resistor changes as well.

In the last pic (vintage block logo) you can see an extra:

2 x 10k
2 x 100k?
2 x 56k
1 x 2.2k
.01u
680pf

Here is a pic of the vintage block Phase 90 with all the parts marked off that correspond to a script Phase 90 with feedback resistor:

RED - Input 10k .01u	YELLOW - Phase Stages 8 x 10k 5 x .05u 5 x 22k 4 x FET	BLUE - Power/Bias trimmer 10k 10u zener diode polarity protection diode 1M 470k ?? 1M here?
GREEN - LFO 3.9M 4.7k 15u 2 x 150k 470k .01u	ORANGE - Mixer/Output 4 x 150k 56k .05u transistor	Leftover 2 x 10k .01u 680pf 150k 2.2k 2 x 56k

So, where do the leftover parts go? Good question.

Here is a pic of the late block Phase 90 with feedback resistor (R28) and C11, C12 circled: