Three people. One question. Three different answers.
I've been in that meeting more times than I can count. Someone asks for last quarter's number, three departments pull their own version, and now the meeting is about the spreadsheet instead of the business.
Nobody is lying. Everyone is right inside their own file.
A reporting system isn't a tool. It's an agreement about which number is the number. The tool is just where the agreement gets written down.
If three people can produce three answers, the problem isn't the data. It's the absence of a system.