QA Distiller licenses are so-called floating licenses, which are retrieved over the Internet from a central license server hosted by Yamagata Europe.
This means that you can install and edition of QA Distiller on as many computers as you want. If a license is available the license server allows the application to run. When you close QA Distiller the license is automatically reclaimed by the license server and made available again.
If you own an Enterprise edition with 5 concurrent users, you can install QA Distiller on all the computers of one department. Five users will be able to use QA Distiller at the same time. When one user closes QA Distiller, this license is immediately available for another user.
You only pay the price difference if you upgrade from one edition to another.
You can simply upgrade your edition by sending an e-mail requesting an upgrade to firstname.lastname@example.org. An invoice will be sent, payable in 30 days.
Let's say you own a Professional edition and you want to upgrade to an Enterprise edition you would pay €2500 - €1000 = €1500.
The Untranslatable feature works in a different way. The items in these lists are considered okay to be left untranslated and will not produce a forgotten or partially forgotten translation error. QA Distiller does not check if they are left as in the source; it is a feature to reduce false positives.
You can use this feature to add terms like Windows XP, Windows Media Center, ... so you no longer get forgotten errors on them.
If you want to check if terms have been left untranslated, you can either use a dictionary or regular expressions.
QA Distiller only counts the number of quotation marks if they are valid for that language, i.e. if they are specified in the language settings.
If straight quotation marks are used in the English source, and the language settings for English only specify curly quotation marks, these straight quotation marks are not counted and QA Distiller thinks there are none in the source. If the correct quotation marks are then used in the target, QA Distiller will report that the target has more quotation marks than the source.
You can solve this by adding straight quotation marks to the English language setting.
You can manually check for updates via Help > Check for updates. You can also configure QA Distiller to automatically check for updates via File > Setup > Update.
QA Distiller uses so-called user lists to store customized settings. These are normal windows folders with a set of configuration files. You can find all the juicy details here: How to set up and use profiles.