case 1 : stays in hPLMN
case 2 : stays in vPLMN
in both case, the MS doesn’t even search for another PLMN. As you quoted from 3GPP:
18.104.22.168 In VPLMN of home country
a) The periodic attempts shall only be performed in automatic mode when the MS is roaming in its home country;
In my opinion, there is indeed a hard distinction roaming to a vPLMN from same country or vPLMN from another country:
In the “border” situation, the MS is roaming to another country. So the MS Timer is not activated, and the MS will never try to come back to hPLMN.
UNLESS the MS looses coverage from vPLMN (case where rxlev < rxlev access min) or some interference issues where the BCCH can't be decoded. Well, that's how i see it...