Warm Up Regulator with enrichment ports

[Ben Swann]

I just installed a variation on Warm-up regulator
035 133 403 D

My '87 5000 Turbo quattro avant as I needed a replacement, and I'd like to
take advantage of the vacuem/boost enrichment feature.

It has the two (one small, one large) ports, which I understand are for
enrichment, in addition to the atmospheric pressure compensation port.
 There is a picture of this unit in Water-Cooled Volkswagen Performance
Handbook by Greg Raven p.120, and description in Probst
Chap.5 fig. 5-6

Are both ports for load enrichment, that is, are both the small and large
port used for enrichment (decreased control pressure) under boost and/or
increased control pressure under vacuem?   I am confused as to why there
are two ports.

I do not have any diagrams for this, but reading both Probst and VW
performance handbook indicates this was used in 5000 turbo application. but
apparantly they did not use on the later ones.  Wonder why?

Ben