If somebody is only getting a top-heavy minimum, how does that affect allocations calculations? Where the plan calls a step that is comp to comp, do you exclude that person (the person only getting a top-heavy minimum) from the eligible compensation? If anyone has a spreadsheet depicting such a case, feel free to e-mail it to me.

Not sure I undestand. For allocation purposes, you first make the non-top heavy allocations as per the Plan doc and, if the Plan was top heavy for that year (generally based on assets in the plan as of the end of the prior plan year), you then make a TH allocation to those who have not already reached the TH minimum (either 3% or the highest allocatin rate for a key employee). If, on the other hand, your question is whether the compensation of those receving only the TH allocation is included for purposes of determining if the deductible limitation has been exceeded (25% of aggregate compensation for a PSP), I think the answer is YES--otherwise, you could make a 25% of compensation deductible contribution taking into account only those eligible for that allocation (say, e.g., those with more than 1,000 h/s in the py), but then would be exceeding the 25% limitation after the additional TH contribution if you could not also include the compensation of those receiving the TH allocation.

What if this person would not receive an allocation at all?

Who is "this" person? Please spell out your question, detail by detail. I still have no idea what you're asking.