regarding detailed information about discounted subscription plans

[Swarnim777]

sir, 

•  We want a subscription plan on our business account for a minimum batch of 500 members. We searched for a plan but there are sufficient plans for 300 members. So, please send us detailed information about the plans meeting our above requirements ASAP. 
•   Secondly, if we purchase a plan for 300 members at this juncture, can we modify the purchased plan to 500 members ?
• Thirdly, On 1 license how many no. of devices can be connected simultaneously ? do let us know ASAP...