let me give it a try....

1.你现在contract的薪水是agent发还是employer发？如果是employer，make sense。agent拿你rate比例的，你高他也高。

2."加了5000"--根据我的经验，你转permanent,他们会拿一笔钱的，根据你的薪水，比例不同，越高的薪水，他们的比例就越高，具体多少我不知道，但我们这边的情况，senior vs. junior能相差20k。

3."agent wants to be involved in the whole process"--money wise, understood

4."I am willing to take a lower salary"--no, stay tall, 如果money is not issue, 他们会pay rite people rite money.

what u need to do is: show ur appreciation/flexibility/willingness to help them out. it's all.

good luck!!