Thanks for the images - that helps
1 Are you using rows 1-4 for anything else?
2 Are you using rows 7-9 for anything else?
Which way do you want the table to expand?
1. leave the size of rows 5 and 6 unchanged, line up bottom of the box with bottom of row 6, allow the box to grow upwards altering the height of rows 3-4 (ie always fits between rows 3 and 6)
2. leave the size of rows 5 and 6 unchanged, line up the top of the box with middle of row 4, allow the box to grow downwards, altering the heights of rows 7-8 (ie always fits between rows 4 and 8)
3. leave the size of rows 5 and 6 unchanged, allow the box to grow centred on rows 5-6, altering the height of rows 3-4 and 7-8 (ie always fits between rows 3 and 8)
4. Something else???