is it not also a case when the "ß" could be used for names but only when it is from the beginning, instead of replacing 'ss'? not that I know german other then a bit of high school a long time ago, but that would make sense to me.
Being German and from Hessen I can only say: You are absolutely right.
Today, the "ß" (or SZ as it's pronounced) is only used after long vocals. You sure know the yachtbuilder Heesen, in German he'd be written Heßen.