From the posted abstract:

"Although, this estimated P value is very high when compared to terrestrial concentrations, it is in accordance with the predicted high P concentration in the martian mantle as was derived from the SNC meteorites"

All this concentration on Phosphorus is missing the point. Address the Titanium. You'll also note that the curves of the two rocks are similar in shape, with the Titanium and Phosphourus elevated. But look at the Zinc, Nickel, Bromine, and Magnessium relative values. The story depends upon explaining those elements too.

If incompatable elements exist in an igneous melt, they concentrate in the fluid phase but eventually they have to crystallize into some mineral phase. REE's concentrate in late stage pegmatites in felsic rocks, for example. Some elements, especially nickel, chromium, platinum group elements fractionate out early in an ultra-mafic melt, not always as a mineral phase but as immiscible fluids. Do the Nickle and Chromium depletions indicate that this rock went through such a process?

I don't have the time to look right now, but I'd sure like to see the same data compared to that of terrestrial carbonatites (which can include a wide range of rock types and is believed to come from mantle phases.)

just some quick thoughts,
jms