Bottling Hefeweizen-seems like a lot of sugar!

I'm using a couple of calculators to get about 3.9 CO2 volumes to get my Hefeweizen (fermented with Weihenstephan yeast) true to style. I have 5 gallons of beer in my carboy and the calculators are giving me a priming sugar amount of about 8-8.3 ounces of priming sugar.

This seems like a lot to me! Do I run the risk of bottle bombs with this much priming sugar?

I've have my beer in secondary for 10 days, so I'm not worried about restarting fermentation of malt sugars.

I used 5 and a half oz's for my hefe (6 gallons) and it's fizzy as hell. Apparently that's only 2.6 vols of CO2 but it's as fizzy as any hefe I've tried.

I go for 3.5 and like it...I think that was ~7oz of sugar and it did look like a ton, but I've had no problems in over a month with any Hefe-grenades.

I went with 7.2 oz (mass) of corn sugar after searching these forums. I'll probably be happier that I went with an ounce less than I was getting from the calculators, as sometimes commercial hefes can be a pain to pour with all the carbonation.