As stated numerous times, increased AR's in immature cells would make logical sense since they are turning into androgen dependent cells.
There are conflicting papers on this subject and your paper doesn't even site the activity of Deca, it says "similar" results.
Fertil Steril. 1979 May;31(5):552-61.
Competitive progesterone antagonists: receptor binding and biologic activity of testosterone and 19-nortestosterone derivatives.
Reel JR, Humphrey RR, Shih YH, Windsor BL, Sakowski R, Creger PL, Edgren RA.
Testosterone and 19-nortestosterone derivatives were evaluated in a developmental scheme designed to identify competitive progesterone antagonists having abortifacient activity. Compounds that displayed significant binding to the rabbit uterine progesterone receptor were followed in biologic tests for progestational, antiprogestational, and abortifacient activities. Of the seven compounds tested for both progestational and antiprogestational activity, only one, 5 alpha-dihydronorethindrone, behaved exclusively as an antagonist. Five other 19-nortestosterones (19-nortestosterone, 17 beta-hydroxyestra-4, 9(10)-dien-3-one, norethindrone, norethindrone acetate, and R 2323) proved to be mixed agonists/antagonists. 5 alpha-Dihydronorethindrone, norethindrone, and 19-nortestosterone terminated pregnancy during the postnidatory period in rats; in addition, the latter two compounds inhibited progesterone-supported pregnancy in spayed rats and curtailed pregnancy during the postnidatory period in hamsters. These results demonstrate that several 19-nortestosterone derivatives bind to the uterine progesterone receptor and behave either as antagonists or mixed agonists/antagonists.
At some point it would seem that any concentration androgens can stimulate the PR, as shown in this article so, showing activity at a high concentration isn't reserved to deca.
Methods Find Exp Clin Pharmacol. 1997 May;19(4):215-22.
Estrogenic and progestagenic activities of physiologic and synthetic androgens, as measured by in vitro bioassays.
Markiewicz L, Gurpide E.
Mount Sinai School of Medicine (CUNY), Department of Obstetrics, Gynecology and Reproductive Science, NY, USA.
Estrogenic activities of testosterone (T) and 5a-dihydrotestosterone (DHT) were detected and measured by using their specific stimulatory effects on alkaline phosphatase (AP) activity in human endometrial adenocarcinoma cells of the Ishikawa Var-1 line. These two physiologic androgens were able to induce, at microM concentrations, estrogenic effect believed to be mediated by the estrogen receptor (ER) since the antiestrogens ICI-164384 and 4-hydroxytamoxifen (OHTam), but not the antiandrogens hydroxyflutamide (OHFl) or cyproterone acetate (CPA), reversed that effect. By using another in vitro bioassay, based on the progestin-specific stimulation of AP activity in cells of the T47D human breast cancer line, progestagenic activity was detected and measured in T, DHT and three synthetic androgens: nandrolone (19-nortestosterone). 7 alpha-methyl 19-nortestosterone (MENT) and mibolerone (7 alpha, 17 alpha-dimethyl 19-nortestosterone) (DMNT). While progestagenic effects of T and DHT required relatively high concentrations (microM levels), the synthetic androgens stimulated AP activity at nM or pM levels. These effects seem to be mediated by the progesterone receptor (PR), since they are completely abolished by the antiprogestins RU-486, ZK-98299 and ZK-112993, but not by the antiandrogen OHFl. These simple in vitro bioassays, expressing biological effects of the test compounds in human cells in culture, revealed dual or multiple hormonal activities coexisting in a single compound and provide quantitative information of considerable pharmacological importance concerning the complex actions of drugs.
Even so, where is the paper showing that progestational activity is partly the cause of gyno, even more so, where is the proof that normal prolactin levels or even higher than normal cause gynocomastia.