Your seat should have gone up 5 mm which is 1/2cm which is about 3/16 inch.

If your seat post is that much longer with the new bike it must be because it's a totally different type of bike - for instance a compact frame with a shorter seat tube, or because it's a smaller frame.

If your saddle to bar drop changed a lot from the one bike to the other, it's because the head tube on the new bike is smaller - either because it's the way it was designed or because the new frame is a lot smaller than the old one.

What are the seat tube, effective tt and head tube measurements between the two bikes?

I don't believe there is any practical way to make up 2" with a new fork with a carbon steer tube. Assuming your current fork has no spacers above the headset (nothing - not even a conical spacer), and you want to max out the new one, you'll can only gain 40 mm = 4 cm = which is a little more than 1.5 inches. This is because the maximum number of spacers between the headset and the stem that I've ever seen for carbon steer tube (1 1/8") is 40mm. Even if you add a high rise stem, you'll only gain another inch or so.

My bet is that you really need a larger frame or one that is specifically designed w/ a larger head tube for a give size.