I can do the job. However, I must alert you that Excell macro security is easy to crack for somebody with good knowledge (not a hacker). So your security would work for standard excel users.
Haven't seen in depth the link you sent, but seems to work creating a log file somewhere in the hard drive. I think it would be better for the excel file to keep track of the number of times it's been open or the time since first open.
I'm an engineer with advanced working knowledge and experience in Excel, VBA and VBA interaction between different software (Word, Excel, Powerpoint, Outlook, Access, Autocad, Project, etc.). Also, have lots of experience with processing very large data files in different formats with VBA (especially data acquisition files). Proficient coder in VB.Net, C#, Python, VB6.