[TYPO3-mvc] Strange UID Counting?

[Christoph Werner]

Hi All!

I´ve build a simple extension via the extensionbuilder. 
Everything works like expected, but after having a look in the database, I saw something strange:

The UIDs don´t count 1,2,3, but x * 256.   
One deleted has 1000000000 (highest UID before: 307200), new or copied entries count 1000000001, 1000000002, 1000000003... now.

Questions
1.) Is the x*256 a normal bevaviour?
2.) Is there any option to influence the uid-generation process?
3.) How can the 1000000000 be explained?

I´m using TYPO3 6.2.17

Thx a lot!
Chris