At least once a year the company would be required to do a 409a valuation to set the FMV for those underlying common shares and thus the strike price for any options in the next year or less. The 409a valuation for common shares is pretty much always going to be significantly discounted vs preferred for a variety of reasons like lack of liquidation preference, lack of liquidity, etc. These discounts are often 50% plus, but the shares likely have a 1:1 economic value to other share classes in a sale, except the most recent preferred that get to use their preference.
Anyways the reality is going to be determined by each company’s details, but option strike prices at private companies are generally much lower than the current going price for preferred due to the discounts provided by the 409a valuation.