I don't know what is your exact requirement.
According to your requirement and alternative for your problem, what i found
Try this, may be this will solve your problem
Thanks for the suggestion, we had explored the above extension and it doesn't provides the functionality which we are looking for.
Requirement - Bar plot with dynamic buckets based on user selection or Histogram with option of calculating expression instead of showing frequency. The histogram provided in Qlik release doesn't take expressions and by default calculate frequency.