There are some issues in FTPSync regarding RetryDelay/RetryCount parameters. A combination of a bug in counting routine along with a bit unclear algorithm on how counting is done may result in vary strange behavior, where number of times to repeat an operation can be way different than what is set in RetryCount parameter.
For this reason I've redesigned the algorithm. The RetryCount/RetryDelay parameters are now strictly used for a single item (directory or file). Thus a single file or directory is retried RetryCount times with RetryDelay pauses in between, before FTPSync gives up on that file or directory. On the other hand, new parameter MaxErrors now dictates how many items can fail, before synchronization as a whole is considered failed and aborted.
This update is available in FTPSync 2.8e or later.