Setting this value to true can often increase performance and output quality at the cost of memory consumption up to a certain number of pages. The more complex the pages, and the more deviation between the page's layouts in a single document will lower the number of pages that should be exported to a single sheet. As mentioned, the complicity and deviation of layout between the pages drastically effects this number, but a guess would be greater than 30 pages would be suitable for MultiSheet=false.