I taste it, but have no idea at what PPM level. I think just about every fruit wine I've bought from a local commercial winery has over sulfited to the point that its noticeable. These are typically sweet winces since the sugar will bring back the base fruit flavor and help sell it as a fruit...
I suppose a good question is how do commercial wineries bulk age their wines in barrels or carboys for years, while keeping under the legal SO2 limit, or even the sensory limit, which could be as low as maybe 1/3 the legal limit (100PPM)? There's no way they can be opening up the barrels or...
My understanding is different, that the legal limit applies to TOTAL SO2, since bound/neutral SO2 will essentially unbind when ingested. Though I just read that somewhere on the internet. There's also the small amount of naturally occurring SO2 to consider, which could even be around 10-20...