Logic Masters Deutschland e.V.

I don't post enough easy puzzles, so here ya go. I beg someone to make a 9x9 version. I had planned on it but have run out of time and now with the school year started, won't get a chance.

The Rules:

1. Normal sudoku rules apply.
2. Numbers in circles represent the difference between the highest and lowest digits in the up to 8 surrounding cells.

The Puzzle:

Try it on Sven's Sudokupad