When designing a responsive layout is it right to assume the iPad layout will be the same as the desktop?

When designing responsive layouts I tend to do 2 sets of wireframes. I design for both mobile and desktop and assume that the iPad will adopt the same layout as the desktop due to size. ( this is if the function of the iPad site isn't dissimilar from desktop). Is this a correct assumption to make? Should I be putting more thought into the iPad layout and be designing separate wireframes for this platform? (even though the iPad site won't do anything different from the desktop).

The other question I had is shouldn't I align the iPad design more to the mobile as the interactions are the same? Despite more real estate to play with on the iPad. Does designing mobile first do this for you anyway?