My 2 cents
You can experiment with engine oil even blend your own mix but transmission oil especially the automatic there are standards there's and many I have seen auto fluid for range rover which was transparent and for 140 per liter and mercs c240 its was like 85 per liter and the then there's the t4 ,WS,jmatics ,dmatics ,ns2,the Dex brothers like 1 2 3 and 4 the BMW have even invented a lifetime transmission oil but that too has to be changed at the agency as that oil is not available outside...
so if you toped up a little. I think it should be OK but if you drain and fill the wrong type of oil it should work at beginning but the clutches will deteriorate sooner then their expected running life then there is one more thing your gear bearings will survive as they only need lubrication from those oils nothing more
the manufacturers have also started to make such trannys that dont have fill plugs and level gauges and some might have but make it difficult to get to so people won't tinker with it...
until