Some couples may choose to follow this cost guideline, but in the end a couple should be comfortable with the amount they choose to spend regardless of how many or how few paychecks are needed to pay for the ring.
The idea of spending the equivalent of two months' salary for an engagement ring is a guideline perpetrated by the diamond industry that has no real bearing on what a couple should realistically spend.
According to their website, although they don't have to meet any U.S. Food & Drug Administration guidelines regarding sodium, they state "we maintain a self-imposed guideline to ensure great taste and good health..."
This table is only meant to be a guideline.
Again, this is just a general guideline of where you might want to be; if you're far from it, a sample diabetic diet 2000 calories can inspire you toward restoring balance to your weight and your health.