85% PM efficancy - no good?

So last time I brewed I got about a 60% efficancy, so this time I decided to overcompensate. I added a little bit extra grain to the bill. After brewing it looks like I got an 85% efficancy. I'm pysched, but with my over compensation of grain and increased efficancy my OG is a lot higher than I would have liked (was shooting for about 1.052 and got 1.063). This could have been avoided had I just not added as much DME. So my question is after mashing and sparging how can I determing what the OG is going to be. I know that I can take a reading and adjust for the temp, but my wort collection is only 3 gallons (pot size), so how can I calculate what my OG will be after I add 2.5 gallons of water for a total of 5.5 gallons?

My second qustion, how do I deteremine how much DME to add at that point in time? I guess I'm asking how do I know what each lb. of DME will add to the OG of 5.5 gallons? Thanks.

ProMash will be able to give you all these calcs. That's what I use. Even if you don't feel like paying the $25 for the registered version, you can still get the calcs from the trial version (it doesn't "expire", you just can only save a limited number of recipes). I'm sure there are some rather complex calcs you could do, but if you just download the trial of ProMash, that should do it for you.

Target gravity points = target volume x target OG (5.5 gal x 52 = 286)
Actual PM gravity points = collected volume x PM gravity (3.0 gal x 50 = 150)
Gravity points needed from DME = target - collected (286 - 150 = 136)
DME needed = "missing" points / 46 (136 / 46 = 3 lbs)

I just made up the 1.050 OG for you PM...plug whatever number you really get in there. And your DME should be somewhere in the range of 45-46 pts/lb/gal...I just used 46.

I'll probably get some brewing software one of these days, but I'm a very math oriented type of guy so I like to be able to do the calculations myself. Thanks Bike N Brew for coming through again with the calculations.

Just out of curiosity, what did you do differently to get your efficiency higher? I would like to get my efficiency a little higher for my PMs also.

I did a few things differently. One is that I mashed out for the last 10 min of a 60 min mash. Also, instead of doing a two batch sparges I only did one and I let it sit for 10 mins before collecting the wort. Before I did two batches with only letting it sit for 5 mins each before collecting. And even though I was using the same mash tun I seemed to hold my mash temp better, why that is I don't know.

For the mashout what temp was your infusion? I've seen some do boiling and some do lower.

I added boiling. I had 6.75lbs of grain with 1.25 quarts per lb for the mash. I held the mash at 155*. Then I added 1.5 quarts boiling for mash out.