Did you have a double glazed glass on the bench between the two devices? 
If not, speed is not comparable, let’s say that you lose 1 Mbps because of the 75 m distance and 499 because of the glass.
Can you try (briefly) what do you have with the window open?
Are you sure-sure that you have no way to put the now indoor device on the window sill?
Like (only as an example) a flat ethernet cable?
CAT6/PoE suitable ones do exist (even if they are not exactly cheap) example:
https://www.waveform.com/products/ethernet-window-entry-cable
In any case, rather than screenshots, post your configurations, following this:
http://forum.mikrotik.com/t/forum-rules/173010/1