SAP Analytics Cloud: When linking a model, data changes automatically

Dear colleagues,

Let me state first the situation. I have 2 models, linked only by dates (Start date for model A and Begin date for model B). When I make an average ratio for model A (let's say "Done projects" / "Total projects") I get a numeric value (0,8). However, as soon as I link a new dimension from the other Model (Model B), the ratio's value changes (6,22) and therefore, I obtain wrong values for any other calculation involving this ratio.

Any clues of how could it be solved or why could this happen?

Thanks a lot in advance.

Best regards,