I think the Associate Professor scale often has considerable overlap with the Assistant Professor scale. The maximum may not be that different from the Assistant maximum.
Getting the title Associate Professor usually, but not always, coincides with getting tenure. Starting from scratch at a US university this might typically happen after 5-7 years. Experience elsewhere would be taken into account though - if you're already senior enough you might go straight in at Associate level. However, you may not automatically get tenure - there would still be a tenure review at some point.
Perhaps send me PM if you want to discuss this more.