Mash temp and fermentability?

I intended on mashing in at 154* to produce an Amber Ale with more body
The temp had fallen to 150* 30 minutes later.
So I added water to raise the temp back up to 155* and let it mash the remainder of the hour.
My question is...
Am I still going to get a wort with less fermentables even though I went 30 minutes with a mash temp between 150* and 154* for half an hour, or does raising the temp mid-mash change the amount of fermentable sugars?
Sorry, this was the best way I could think of to word it.

No way to know for sure until you taste it or until it finishes (FG).

However, you may have made the wort more fermentable and thus have a lower FG. Not much you can do at this point, but I wouldn't worry about it.

You could always sanitize and add carapils/carafoam to add body. I've never done this, but an employee at the LHBS mentioned that he has done this with success.

I mash in a cooler and often have a variance in temp over the 60-75 min. You could invest in something like this. What I do is watch the temp closely and write down what it's at every 10 minutes. With a remote thermo it becomes quite easy. This way if you want to correct your temps you know when to do so or you can do what I sometimes do and just document it rather than correct because it may make really awesome beer and now I have the notes and times to recreate that beer.

As for what to do now. I dunno, ride it out and see what happens. It'll be beer either way.

I would advise against that thermometer! Actually I have the weber version but I think they are exactly the same. For one, it only works 20% of the time. It is also about 6 degrees lower than my other quality thermometers. It's made for meat, not accuracy. A decent cooler will keep temperature constant over an hour. To do it on a stove takes a little more attention but I kept 152 for an hour with only a deviation of 1 degree.

Thanks for the replies.
I guess I'll just ride it out.
Either way I'm sure I'll like it.
The previous batch turned out great. Only difference is I switched up a pound of Victory for Special Roast.
Got the recipe from Brewing Classic Styles. I thinks it's a great book. Lot of good info on styles, and keys to brewing each style.

All other things being equal, a mash that went 154 to 150 to 155 will be more fermentable than one that sat at 154 the entire hour. How much more is beyond me ;-) Probably not that much at all.