Change your Ratio calculation FROM: [Sales Forecasted]/[Actual Sales]
TO: SUM([Sales Forecasted])/SUM([Actual Sales])
Right now, you're computing a ratio for each month then summing all the ratios together (hence the SUM around Ratio in your screenshot). That is actually returning 666% and 684% respectively, it's just displaying as a decimal.
Use the above calculation, then make sure you format your numbers as percentages, or you will just see a 1 as it's rounding anything above 50% (.5) up to 1.
Thank you!, got it.