I just went and played with the dog after all your corrections and realized her yard is a little higher than mine across the fence. Thanks for all the research it was very informative.
That makes sense, if their yard is elevated, the dog will appear taller than it is.
Mastiffs are generally very nice dogs. I have never horseplayed with mine, but the very tall grandsons do, and it’s truly fearsome! They like it, but normal humans should stay far away. :D