When specifying an initial base value using 'BaseValue no changes are made.

For example,

y = [8 15 33; 30 35 40; 50 55 62];
barh(y,'BaseValue',25)

fig2plotly(gcf, 'offline', false);

The previous code should produce an horizontal bar chart in which the 'zero value' or base value should be 25, however, it starts at 0 as usual.

Expected and generated (https://chart-studio.plotly.com/~xarico10/573/#/) plots:

Examples on using 'BaseValue can be found on:
https://www.mathworks.com/help/matlab/ref/barh.html#mw_caa2d25c-e3b8-47db-ad74-c7643062cbf8