不一定，加注的簽證僅供移民官參考

My parents got 3-month annotation on the visa stamp. I wrote a letter to USCIS officer at custom and they got 6-month stamp on I-94. You can ask your parents to talk to officer and explain why they need more than 2-month (long trip, need time to recover, travel plan, etc.) or you can write a letter to explain. Usually they will get 6-month. In some cares, people get 6-month anyway with 2 or 3-month annotation. So it is not something certain, you need to request for it. Whether or not they can get it, it depends on the officer. Good luck,