Calculating table height

I am dynamically creating a table and table rows on a slide to show data from a database query.  All works great until I try to determine when I need to generate a new slide and start a new table.  My problem: every attempt to compute the height of the table does not yield correct results and my table exceeds the size of the slide.  My current table height computation method is the sum of the row heights. 

Could you please post some of your code, so we can do trouble shooting.