Pistoler0,
I am having a bit of trouble visualizing what you are describing. I can tell you that some rifle stocks have an adjustable rest under the toe of the stock to raise it to level with a bi-pod (Choate varmint stock, for example). The comb of your stock may be too high and cause interference with getting your head low enough. Your bipod's minimum leg height may be too tall and you need a shorter one (testing with the bipod folded or removed and using stackable sandbags as the front rest will tell you. That's an experiment you can conduct in your house (after the following Jeff Cooper's dryfiring admonition to clear the weapon and lock all the ammo in a box or drawer that is in another room).
If you get a photo from the side and from the front of the gun and send it to a stock maker, they may be able to tell you right off what is happening.
For the spine alignment argument, I think something is being lost in translation. Unless I am missing something, to get the bore line coincident with the spine, you would need to line your spine up with the target and then rest the rifle's butt on your forehead, letting someone else with a dental mirror report to you when the sights were on target. Trickshot stuff. But if by "in line" Mark Means parallel to the spine, that is not impossible, though it is not the prone position I was taught.
