You can easily add more members to the Monthly/Yearly plan. They will be billed at the rate of the respective plan, for the remaining time (till the next billing cycle). Let's look at these 2 examples in Yearly and Monthly plans:
For example, you are using the Elite (yearly) plan at a rate of $3.5/user/month. You will be charged $3.5*12=$42 per user for a year. If you have 5 employees, you will be charged $42*5=$210 per year.
If you add members in upcoming months, you will be charged for them at the same rate of $3.5/user/month. You will be charged for the remaining period till the next billing date.
That is, if you add 1 employee after 6 months, you will be charged $3.5*6=$21, at the time of adding this member.
From the next billing cycle, you will be charged for that person as a regular employee. That is, now you will be charged for 6 employees, i.e. $42*6=$252 per year.
If you are using a monthly plan, if you have purchased your subscription plan on Day 1 of a month, you will be always charged on the 1st day of all months.
When you add a member on the 16th day of the month, you will pay for the remaining days till the 1st day of the next month.
For example, you are using the Elite (monthly) plan at the price of $7/user/month.
Now, if you add a new employee when 15 days are remaining till the next billing date, you will be charged for those 15 days only (not the whole month). That is $3.5 for these 15 days.
From the next month, you will be charged for him at the regular rate of $7/user/month.
N.B. VAT may be applicable based on your region.
How will Apploye charge when removing members in the middle of a month/year?
For the removed members, Apploye will keep their unused time in mind. The cost of that time will remain as credit, which will adjust on the next billing cycle.
For example, if you are using the Elite (Yearly) plan ($3.5/user/month) and you remove a member after 6 months, the cost of remaining time ($3.5*6=$21) will remain as credit. This will be subtracted on the next billing date.
If remove someone in the middle of the month in the Elite (Monthly) plan, credit adjustment will be similar, based on the number of remaining days for that month.
To learn more, please go through this article How will Apploye adjust billing when removing members?