alliegad

I have the project options set at 4 seconds per slide, but I'd like the second to last slide and the last slide to linger for much longer. I click manually on the second to last one and get the pop up that says main - timing - use own preference - where I enter 10 seconds. I preview this over and over and it never lasts more than 4. What am I doing wrong? Any help? Thanks so much in advance...