It seems tax authorities can be surprisingly flexible as long as they don&#x27;t get a whiff of attempted tax evasion anywhere.<p>E.g. at some point around 2000 or so, I&#x27;d just moved to the UK, and my personal finances were total chaos around the move. I&#x27;d sold quite a lot of shares in Norway, and traded quite a bit on NASDAQ via a US brokerage account (in 2000... yes, it got ugly; thankfully not that much money), and had income from both UK and Norway split between employment and contracting in the same tax year. And transfers back and forth between my UK, US and Norwegian accounts... To make it more annoying, UK and Norway have different tax years (Norway follow calendar year, UK does not). And to be honest my record-keeping at the time was shoddy to the extreme.<p>So I wrote a letter to UK and Norwegian tax authorities where I set out the details of my income, assets and losses as best I could. I told them I had no clue how to accurately figure out exactly what was due (for the US it was easy because it was all losses that year; the US brokerage account was just relevant because it provided deductions for losses on my Norwegian taxes). Gave them a number each that I thought was close to correct. Filled in my tax returns with estimates (and explained in my letters that the numbers were estimates). Both just accepted my estimate with no arguments, and no requests for further documentation. No fines, or angry letters, or conflicting estimated tax calculations or anything, which was what I feared when I sent it all off.