MultiBeast - how many times can I run it?

1) Files saved from one MultiBeast session won't load in the next session. I get a "Configuration file corrupted". Is this normal?

2) What happens if I run MultiBeast multiple times? Will it create more EFI partitions? I'm asking because now in BIOS I see two "Mac OS X" entries. Is this because I run MultiBeast two times or because I have 2 SSDs (dual boot with Win10)?

So, question is: is it safe to run MultiBeast every time I want to make a change?