Hello Vilas,
Yes you are right, but I was just happy to discover something new.
To come back to the issue, yesterday I flew another A 321 quite heavy (over 80t) and at some point we were cruising at FL 320 at Mach 0.72 due to traffic ahead. Anyway and I could see the green dot sitting exactly on top of VLS ( VLS was there this time) and during turn at waypoint, the VLS was moving slightly up but the green dot was moving up also and never went below VLS at anytime.
That's why I'm a bit surprised.
I'm not saying you are wrong, I just never saw green dot going below VLS or worst Alpha prot before. Maybe it happens like Wille Nelson says in hold with steeper turn but I never noticed it. I'm still junior on type.
Next time I'm holding I will check that carefully.