Conditional formatting & 1 column to the right?

In the attachment column A contains a number and some conditional formatting that states 'if cell value is' greater than the number in column B to go green and if it is smaller or equal to go red.

Every month I add a column between columns A & B to put new volume figures in. But by doing so the conditional formatting formula automatically changes itself to reference column C instead of column B.

Is there a way to use the formula function in Conditional Formatting to always read the cell to the right of column A so I don't have to update the formatting every month? My actual spreadsheet has loads of rows so changing the formatting is a bit tedious.