Thank you for your reply. As you mention MMP 10 in your post, perhaps I should mention that I do not agree with the belief that this problem refers to the surface area of a semi-sphere. Rather, I think that Peet's second alternative explanation is the most plausible, and that it involves the surface area of a half-cylinder. My suspicion is that the relevance here is that MMP 10 refers to a utensil used to scoop out specific quantities of grain. If the 4 1/2 dimension mentioned is understood to be in "finger" units, then the half-cylinder scoop would hold a 1/2 hinu quantity.
I am preparing a paper on MMP 10, and my present interest in RMP 48 is in part a result of this.