ayup. piercing the big end is SOP for me. the older the egg, the bigger the air sac, the more likely the build up of internal pressure will find a weak spot.
you might find this info illuminating for the whereas and howfors... it's a bit a a long read, but actually the temp / advice at the near end is the most valuable part.
http://www.seriouseats.com/2009/10/the-food-lab-science-of-how-to-cook-perfect-boiled-eggs.html
snippet:
/quote
Since whites set at 155 degrees and yolks set at 158, you have a tolerance of three degrees to work with, which translates to about 15 seconds in either direction.
/unquote
basically, all the home spun methods of start cold/hot/turn off/wait x minutes etc etc etc - all depend on a lot of variables - egg temp to start, amount of water, burner performance, temp of boiling water (ie altitude) among the biggest. this is why the homespun methods work absolutely perfect for one person, and bomb in the next kitchen.
I start them in boiling water. when we got a new fridge, I had to rework my timing for soft / hard boiled because the new fridge keeps colder than the old one....
the narrow range of "really good" finish temps makes the sous vide method very attractive - brings the whole egg up to set temp and can't "over cook" - if you've got a couple hours to wait for your breakfast eggs....
otherwise you've got much higher heat "outside" the egg, creates a temp gradient to the "inside / center" and you have to find the right balance point (ie time) for the way you like your eggs.
using the same pot, on the same burner, set to the same heat level, with the same amount of water, at the same water starting temp, the same number of eggs of the same size, eggs at the same temp - yup, one can experiment and "find" the exact time needed for cold/hot start + turn off on boil & wait, etc. not a problem - the "problem" is only "some experimentation required" - with perhaps a few things out of your direct control - such as the temp of "cold water" coming out of the tap, by season....