When on cycle, the HPTA will shut down and the testes are likely to shrink. When you get off the gear during PCT, the HPTA will try to start. LH should resume, but if the testes are physically weakened, then they will need to physically grow again when stimulated by LH and will not be able to respond with full T production until they recover. So that is dead time that you do not want.
Large doses of HCG can be used in young boys to try to get undescended testes to drop. Doses for female fertility treatment are very large. You will find a lot on the net, and here, about using thousands of IUs per injection. You do not want to that because down regulation of LG receptors is the last thing that you need.
To boot start, 1000iu for two days in a row, followed by 250iu EOD would be good. Do that for 2 or 3 weeks at the end of the cycle as you taper off of gear and get into PCT. Alternatively, 250iu EOD all trough the cycle and the testes will never shrink and will stay operational. 10,000 iu will last 80 days, good for a 10-12 week cycle. If doing that, start the HCG one week into the cycle.
When guys get 2000, 3000, 5000 iu ampules intended for single dosing of females, that encourages bad practice. Multi use vials are best. SC injections are as effective as IM.
Many get by without HCG and get the testes kicking again with SERMs. There can be issues with long term SERM use.