How are you setting the 150% flow rate?
If you are setting it manually via firmware command or LCD before printing, then using Cura LE will reset that flow rate to 100% after first layer. This is because Cura LE has an “Initial Layer Flow Rate” field which is implemented not in the slicer code, but rather via firmware using M221 commands. Before layer 1, Cura LE sends an M221 with whatever is in the “Initial Layer Flow Rate” field, then before layer 2 it sends another M221 setting 100%. (Note: This effectively means that the “Initial Layer Flow Rate” is not an absolute value, but rather a multiplier of whatever the “Flow” field specifies.)
If you set the 150% flow in the “Flow” field, and set 100% in the “Initial Layer Flow Rate” field, you should get 150% throughout the print – as that 150% will be implemented by the slicer internally, resulting in larger extrusion values in gcode. (Note: The 100% for “initial layer flow rate” is a firmware modifier or multiplier of the base Flow rate used in the gcode commands – so 100% in “Initial layer flow rate” really means 100% of the 150% Flow being used for calculations by the slicer.)