In fact, in 1.7.10, the 'fluid' in the red rectangle (picked from NEI item panel) is identified as Item, not Fluid.
Real fluids in the yellow rectangle have border, and their unit is mB (or B, KB...) .

Any recipe transferred from NEI recipe gui can automatically convert Item to Fluid.
But if you want to add custom recipe which contains fluid, you need to click this Label button to grab the real fluid.

Another problem is that the recipe of most gregtech fluid can not be viewed by press R. One way to solve this problem is to press U, and then view the recipe of the cell containing this fluid.