Surcharges - Baggage Weight

This has always amazed me for the last few years we have taken all manner of things on the uk to corfu leg of our journey and so far have not had a problem we always aim to be on or just below our 20kilo limit this year we had a suit case each total weight 30 kilos and 2 seperate boxes of plastic wallblocks(they look like the glass blocks that that you often see built like a wall so our total weight was 43 kilos we wernt charged any excess the previous year we had a total of 42 kilos 2 suitcases plus a shower tray and electric instant shower unit again no excess charges the previous year going via gatwick we had 2 suitcases plus a workmate bench plus power tools. The only time ive ever had a comment about our luggage was when we bought back 2 of those large 4 litre metaxa bottles on stands and that was at the checkin desk the rep standing close by said we must be planning a great christmas and at the xray machine where the greek security gaurd carried the bottles round the scanner. on the plan the stewardess even moved peoples bags in the over head lockers so our bottles would fit. by the way has anyone ever seen the scales at corfu airport working