HTML tables like that aren't always a "grid" object per say. So, there are 4 rows in the HTML table but one of those rows may contain something entirely different. It would be interesting to see what TestComplete sees in those cells in row 1... could be that they are place holders, filters taht are non-visible, etc. Not that they are "hidden" deliberately by the developer, but the component that they are using for that table may have some other <tr> tags in them that generate a row.
Basically, keep in mind that "RowCount" is a constructed value based upon the content of the table, not necessarily based upon what is visible on screen.
Try recording a short test and click around on the two rows and some of the other objects that are in your screenshot. Then you'll see what TestComplete thinks their names are and that may give you some more clues.
