It appears I might misunderstand the CLI output, as the 'free RAM' calculated from the GUI 'Memory Usage' doesnt match the ''free -m' command output. But comparing the 'used' column output, it looks like firmware 14.5 may be accurate, but firmware 7.01.2 may be wrong in the GUI???
For example using the firmware 14.5 images, the GUI shows 44% RAM used, and taking the used column of the CLI 'free -m' command, we see 27180 out of 61024 used, which equals 44% also.
However, using the firmware 7.01.2 images, the GUI shows 89.3% RAM used, but taking the used column of the CLI 'free -m' command, we see 26760 out of 59972 used, which equals 44.62%??? This is also quite close to the 14.5 firmware result....
This would suggest that the 7.01.2 firmware GUI indication of the RAM used is quite wrong (hopefully)??