with zone_ho_hyst = 20, MS can barely enter the inner zone.
the condition to enter the inner zone is :
Rxlev(DL OUTER) > RXLEV_DL_ZONE + ZONE_HO_HYST_DL
Rxlev(UL OUTER) > RXLEV_UL_ZONE + ZONE_HO_HYST_UL + 3dB
you shall not go below an hysteresis of 12dB, otherwise there will be ping-pong.
higher than 18dB – and the probability to have enough rxlev to enter the inner zone becomes very thin ! so yes, with 20dB you will create more blocking.