I can do the job! I normally perform an in-depth check of macros handling large data. Most practical, reliable and fast check, in my experience, is to have the macro copy same data to the source sheet (in empty columns) this way, with a simple excel function can visually check any missing data.
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 bases and data acquisition files). web scraping, Access DB design, and proficient coder in VB.Net, C#, Python, VB6