Yeah - a great example of clear writing
My understanding (and I am not a pilot, but I have had to calculate net flight paths in my time) would be that you are allowed to make a level flight acceleration at 400 ft or at an obstacle clearance height to get to a speed that allows you to meet the en-route climb gradient requirements.
7.3.2 is not at all clear, but I would read it as requiring that if you went from a level acceleration to a climb at any point you must have at least 1.2% gross gradient available. Since both acceleration and climb gradient are proportional to (T-D)/W this is equivalent to requiring a minimum acceleration capability of 0.012g.
7.5 is a bit easier - when constructing the clearance profile you have to degrade the gross gradients by the gross/net flight path margin. When looking at the bit of the profile that relates to the acceleration segment you must equally add a margin, in this case by adding distance. The bit about "equivalent to the climb gradient reductions" is just saying that the margin to be applied in distance is the same as that which must be applied in the climb segments; that is a reduction of 0.8% in acceleration capability. I think that means you should have an acceleration of at least 0.4% available - and that is a magnificent 0.07 kts per second!!
Hope this helps rather than confuses