I am saying that what you are asking is not part of the Progress Bar plugin, nor is it within the scope of what the Progress Bar plugin should do. The plugin was built to solve a very simple, small task and should not be overburdened with a lot of extra features that stray from the original intent of simply displaying a styled and animated bar.
If you want to inject a random number into the bar, you would first need to decide how you wanted to approach the problem, i.e. whether you wanted to write PHP code or write JavaScript code — as pure HTML does not support the creation of random numbers — and examine the plugin’s source code to get an understanding of how you could integrate the number into the progress bar. For example, does the random number change the length of the progress? If the number is truly random, is there a ceiling to the random number and should the bar reflect progress towards that ceiling? How are you going to ensure that the random number is randomized only once per day and not on every page load? Etc.
Once you have an understanding of how the bar works, and what language you want to write it in, you could then take the code of the plugin — either by downloading it from www.ads-software.com here or by forking it on GitHub — and modifying the source code to accomplish your task.
The beauty of open source software is that anyone can take a piece of software and modify it however they want. My recommendation would be to:
1) outline all of the aspects of what you want the bar to do and write them out,
2) decide on a language you want to use (the task you are asking about could work in either PHP or JavaScript),
3) take the source code of the Progress Bar plugin and examine it so you understand how it works, and
4) write the code!
Even if you did not personally feel competent in accomplishing 2-4, the exercise of writing out your requirements in the first task would be beneficial if you decided to pay a developer to write the plugin for you. But the problem you want to solve is not difficult, and I’m fairly confident that with some research into writing JavaScript or PHP (or both) and possibly some WordPress internals, that you would be able to come up with a working solution.