Generally most of the people who have grandfathered features actually end up paying MORE for the services they are being provided because they haven't modified to more cost effective plans and features in fear of losing that grandfathering.
But, if you only have exceeded the limit twice, why does it matter if you're being throttled? The likelihood of you exceeding the limit that causes you to be throttled is almost non-existant according to you, so what's the problem?