I think you will be okay using the Jiffy. To me if the recipe calls for
a baking mix I don't think what brand you have would matter. The only
thing that would be different would be the consistency and how it may
turn out.

For me I always have Bisquick on hand, because I am normally making
pancakes and biscuits with it. If I had a recipe calling for Jiffy
baking mix then I would be like you questioning the difference, but I
would use what I had on hand.

Good Luck.
Wendy