When using pilsner malt I usually do at least a 75 min boil.. It seems to take longer to do it's stuff than say a pale malt.
As for accurate temperatures. If you want easily reproduceable results they are paramount, if you want to make reasonable beer, they are less important
Near enough should make something you can sit down and relax with.
If you ended up with more than expected the boil might not have been as aggressive as your brew software calculated, but so long as you saw that "rolling boil" you'll be fine.
Also different grains seem to soak up more or less water in my limited experience.
I always add a bit more sparge water to my mainly UK pale driven brew than pilsner for this reason.
From your numbers it seems to me your grain/water didn't quite match up to your gear - don't worry - tweak it a bit for the next brew and your numbers will start to correlate.
I'm just dialling in close numbers for my mini/midi biab setup - of course I'm about to switch to a converted commercial keg so they'll be out the window
Don't stress too much about being a bit off to where the software says you should be at - especially if the finished result tastes good.
It can take quite a while to dial in the right numbers for your setup but all the experiments on the way can be enjoyable.
Let us know how it turns out.
edit: Oh and as for the thermometers I just bought 2 for $12 off ebay and tested them against a certified thermometer - they were both within 0.2C
Second edit: sorry.
The little round ones similar to this http://www.ebay.com....NAAAOxycD9TSL~i
Are about as accurate as sticking your finger in the pot and trying to work out the temp.
Edited by boddingtons best, 03 September 2016 - 02:21 PM.