<font face="Arial, Verdana">Tested on Linux RepetierHost 1.6.0.</font>
Settings under CuraEngine configuration that controls Inner Perimeter Speed do not apply on Slicing.
Investigation shows that field "insetXSpeed" in cura.ini is not updated with GUI stored value for Inner Perimeter Speed, but "infillSpeed" value.
Probably variable linking mistake.
As I understand CuraEngine logic:
<font face="Arial, Verdana">inset0Speed - Outer Perimeter Speed</font>
insetXSpeed - Inner Perimeter Speed<font face="Arial, Verdana">
</font>