PTE/CTE - Plan/Commit to Enroll are AMCAS OPTIONs for you. You are not required to use these OPTIONS unless a medical program requires it in their instructions to applicants. Medical programs advertise their PTE (and CTE) policy in the MSAR and should also devote a section of their web site to clearly defining their policy of use of PTE.
PTE - Is now available for you to select but has little real value to anyone. Until May 1, medical programs can only see aggregate data. This means that they do not know WHO has selected PTE until May 1. To me, using PTE prior to May 1 is a total waste of time. Yes it will tell a medical school that that 25 of their 100 acceptees have selected PTE, but again they dont know who. It is good for bored acceptees who can play the daily PTE game with themselves. I think the most common game is the daily changing PTE game --- if they have 3 acceptances, they choose a different one daily! It drives med schools nuts, they lose a few one day, gain a few the next...up and down it goes ---- the only problem is only a few med schools pay attention because it is AGGREGATE data.
PTE after May 1 has some significance to medical programs. They will begin to see your name and that you have PTE'd to their own program or another unidentified program. Some programs may see that you have PTE'd to another unidentified program and they may either contact you or they may assume you are not interested in their program and rescind their offer of acceptance. When you know that you will not be attending a program please do everyone a favor and withdraw - it is especially helpful to other applicants who are seeking an acceptance.
CTE - Will be available to you starting May 1. Most programs will not require you to CTE more than 3-4 weeks prior to the beginning of their orientation/matriculation week. This is the customary timeframe that was previously included in the AAMC protocols. There are some programs who have set their CTE deadline 7-8 weeks ahead of their orientation/matriculation week. I feel very strongly that these programs are restricting applicant choice, forcing you to CTE to their program while still awaiting "that " acceptance from your top choice program. This is not fair to you. If you find yourself in this situation I would recommend that you contact that "top choice" program and chat with them. Many would like to hear from you and will likely give you an idea if your hopes are in line with the possibilities of acceptance at that program.
IMPORTANT: All med schools make their PTE (if they use this)/CTE deadlines clear and should publish them at their website and in the MSAR. YOU ARE RESPONSIBLE for knowing these dates. If you do not find them at the school's website you should ask them to post it.