Sparge for points, not volume - help a guy out!

This came up in a conversation with a significantly more experienced homebrewer over this past weekend. I mentioned that I undershot my OG on an IPA by a large amount. He then talked about sparging for points instead of volume. I'm still a little unclear on how you go about doing that, though. What he was talking about was similar to this.

However, he described it in a way that makes more sense, if I understood him correctly. Sparge until you get your points or until the run-off hits 1.010, whichever comes first. If it takes 15 gallons to get your points, fine. Just boil it down. But that's where the cipherin' breaks down for me (bearing in mind that I am an artist-type, and can barely balance my checkbook )

Given: need an OG of 1.064 into the fermenter. That gives 320 gravity units for a 5 gallon batch. My pre-boil volume will presumably be 6 gallons. So, 320 points / 6 gallons = pre-boil gravity of 1.053. That's simple enough that even I can get it. Grain bill is 9.5 pounds, so about 3 gallons of strike water, of which I'll be lucky to get 2 gallons of wort.

First runnings: efficiency blows for some reason, and I get 2 gallons at 1.045, or 90 gravity points. First sparge gets me 3 gallons at 1.040, or 80 gravity points. Great, I have 5 gallons in the pot and I'm just over half way to my point total for the recipe! Second batch gets me another 3 gallons at 1.030, so 60 more points. I'm up to 230 points in 8 gallons of wort. So keep sparging...3 more gallons at 1.021, 271 points in 11 gallons. Fourth batch - 3 more gallons at 1.015, 45 more points; 316 points and a ridiculous over-sparge at 14 gallons for a 5 gallon batch. By now, I'm going to call it good enough for gubmint work, eat the 4 points, and start my boil - which I am assuming will last at least 8 hours to get that 14 gallons down to 5. This is called fun?

Now, I know this hypothetical isn't the way it works IRL. So what am I missing conceptually that is not letting me see the forest for the trees?

Not sure I understand this, if you mash correctly you shouldn't have to sparge more than once to get the correct gravity.
No that doesn't look like fun.

According to this page http://braukaiser.com/wiki/index.php/Understanding_Efficiency you should be getting closer 1.085-90 for your first runnings, which would make this technique look much better on paper. I'm not sure if you actually tried it or if the numbers you have were completely made up, but the main idea is good. Sparging a little extra will help you get up to your target OG.

In a nutshell, it's means forget about kettle volume until you have either rinsed the grain bed clean or have realized a much greater efficiency than planned and find yourself with a much stronger beer than desired at your target pre-boil volume.

No matter what your kettle volumes end up being you have 3 pre-boil options;

1. Dilute to target.
2. Supplement with adjuncts to target.
3. Say bless it and boil it.

That's a bad way to brew in my opinion. It opens you up to oversparging and you would have to boil so long that you would get a ton of Caramelization in the kettle. Which is fine for some styles. You should be able to get your process in tune to where you know exactly what you're efficiency is and if you do miss it's only a point or two. If you miss big you either just go with it or get some DME to correct.

Make your process repeatable and you won't have to jerk around with all that math.

That's my .02

Grain is cheaper than propane, if I am not mistaken. Brew for beer.