Graham,
I've created a file based on your description, and created a "macro" solution - which works.
Because you have a situation where you are deleting a formula upon which other formulas rely upon, there is really no way to avoid getting the #REF!
I believe your best option is to use the following (relaitvely simple) VBA code. Activate it after a row or rows are deleted. I've attached the code to a "macro button" which when clicked, restores your formulas "in the blink of an eye".
Sub copy_formula()
'restores formulas - for use when row(s) deleted
Application.ScreenUpdating = False
'turns off screen updating
Application.Goto Application.Range("startcell"

'goes to the cell above the first formula
ActiveCell.Offset(1, 0).Select
'goes down 1 row - to 1st row with formula
Application.Range("frm"

.Copy
'copies stored formula to memory
Range(ActiveCell.Address, ActiveCell.End(xlDown)).Select
'selects range of cells until hitting a "blank" cell
ActiveSheet.Paste
'pastes the formula from memory
Application.Goto Application.Range("A1"

'goes to the A1 position
Application.ScreenUpdating = False
'turns screen updating back on
End Sub
NOTE: For this code to work, it required that you first do the following:
1) Create a "Range Name" for the "starting number". I have placed this "starting number" in the cell immediately above your first formula in cell B12. Therefore, assign the Range Name "startcell" to cell B11. The "easy" method of creating a Range Name is to go to that cell (B11), use Control-F3 (hold down the Control key and hit the F3 key), type the name "startcell", and hit the Enter key.
2) Assign a Range Name to the cell where you will want to "store" a copy of your formula. I have used the cell under your "counter" cell (I1). Therefore, in I2, assign a Range Name called "frm" (short for "formula"

.
3) Then copy your formula from B12 to I2. This then becomes your "stored" copy of your formula - which is in turn used by the VBA code to replace any and all formulas which are affected by deleting rows.
That's it, that's all. "Works like a charm".
If you would like a copy of the actual file, for easier reference, just email me, and I'll send the file via return email.
Please advise as to how you make out.
Regards, ...Dale Watson dwatson@bsi.gov.mb.ca