Ohhh! This is so good to know! You are obviously quite right in stating that it is not to be trusted blindly. This is the second thing I learned today. The first is that walls can shrink! In the process of renovating the kitchen after a water damage. Thought I had everything under control until the carpenters said "we have a problem" when there suddenly was not enough space to hang the last cabinet... Next time I will measure, and measure again! A couple of times!