Evaluating Health Care Options?

My wife’s employer is changing her medical plan by setting up two plans with different co-pays, coinsurance and premium levels.

For the life of me, I can’t figure this out. One plan is has lower co-pays and coinsurance and annual limits but the monthly premium is 18% higher than the other option.

Can anyone suggest a publicly available spreadsheet to work this out or is there a rule of thumb about how to evaluate the options?

Thanks