Finasteride inhibits Type 2 5 alpha-reductase (while Dutasteride also inhibits Type 1, there are only two types) which converts T to DHT (dihydrotestosterone), about 5x more potent than T and responsible for scalp hair loss and body hair growth (and prostate enlargement and probably many other things as well). If less T converts to DHT, then more T is available and some of that may be converted to E, thereby slightly increasing E levels. E does not convert back to T, it's only one way, always T to E. Finasteride and dutasteride do NOT block T or DHT.
Spiro and Cypro reduce androgen levels (and your own E since A converts to E) and block androgens (T, DHT and other weaker androgens) from binding to receptors. Cypro blocks androgen more strongly. Spiro also increases breakdown of androgens, and conversion of androgen to estrogen. Both Spiro and Cypro, being progestins, are also mildly anti-estrogenic and in rats/mices, somewhat androgenic (I don't know if it's the same for us).
E also reduces androgen and also apparently...
http://en.wikipedia.org/wiki/Polyestradiol_phosphate"blocks testosterone uptake into prostate cells, where it would be metabolized to DHT by the enzyme 5α-reductase. Estradiol also inhibits 5α-reductase directly, blocks binding of DHT to androgen receptors, and exhibits cytotoxicity on prostate cancer cells.[4][7]"
So there you go.