The first book in the series, The Girl in 6E, has a unique plot idea. It was excellent. [Note I listened to it on audible. Very good narration for both books.] 
 Do Not Disturb is good but not excellent. The change? The plot here is one that has been done before. No, not with a internet sex worker, but with many a young woman stalked by someone creepy. 
 That said, it is much better than average. It held my interest and the author certainly kept me concerned about the perils of the characters.