Professional to Developer or Higher?

Greetings!

I purchased this product $49.99 (professional) version and have two questions:

1- If I want to upgrade again to the Developer version do I pay $99.99 or the difference of $49.99 (which I already paid)?

2- With the Developer version, will I have the capability to store data (on some form of database) and deploy this information to also be viewed/searched from a website? If not, does the Platinum version support this?

I’m looking to see if I can store data, using this product, then display the data entered in some form of searchable report.

Thanks for your time and valued assistance.