Sean,
in the first plot you specified the FrameTicksStyle as
Directive[Black, 15]
In the second plot you used Automatic which inherited the style from the LabelStyle. Make one change and your plots will match:
FrameTicksStyle -> {{Directive[FontOpacity -> 0, FontSize -> 0],
Directive[FontOpacity -> 0, FontSize -> 0]}, {Directive[Black, 15],
Directive[FontOpacity -> 0, FontSize -> 0]}}
Regards,
Neil
