An automobile insurance carrier may be required to pay lost wages in addition to medical bills when liability is "reasonably clear." The Montana Supreme Court recognizes that an insurance carrier can and will strongarm a victim and their family into a settlement by withholding payment for lost wages.
As you can imagine, insurance carriers have developed a method for attacking claims for payments of lost wages and medical bills. Insurance carriers send claimants to a "doctor of their choosing" in an attempt to cut off medical and lost wage payments. These doctors are bought and paid for by the insurance company. Many doctors are little more than tools of the insurance carrier who are in violation of their Hippocratic oath.
Although there is not a Montana Supreme Court case explaining how frequently payments for lost wages should be made, an insurance carrier usually pays compensation for lost wages at a rate of frequency that the injured claimant typically receives compensation. If you are paid on a monthly basis in your job, you will likely be paid on a monthly basis for your lost wage claim. If you're paid on a weekly or bi-weekly basis, the insurance carrier will typically pay your lost wages over that period of time.