Proviron will bind with a higher affinity to SHBG, and therefor, by all the laws of physics, will displace testosterone from SHBG. That much is true, but no more.
Once testosterone is released from SHBG it is an environment in which it is not easily transported, since it is a lipophillic protein in a watery environment. It is also recognized as being in the wrong place. The result is that it will rapidly be degenerated, transported to the liver for further degeneration and then rapidly excreted. The final result of decreased test binding to SHBG is a drop in testosterone, not a rise. The ratio of free testosterone, as measured in bloods remains somewhat constant, but the total level of testosterone will decline, and the level of testosterone reaching destination tissues (which can't be measured under normal circumstances) will decline with it.
