Well, I don't know about using the vitamins for reptiles, hence I don't, but yes the calcium is the same stuff. I have a source of UV light in my White's enclosure though, so less need for vitamin supplements, so it makes more sense for me to mostly use a plain calcium supplement.
When my frogs were babies I used the Komod amphibian insect dust powder though, then when they got older switched mostly to dusting with calcium.