There are problems that require adding a sample location that is very close to the current sample. Such problems involve Boolean signals in mixed signal domains such as PLLs where a very small latency e.g., a femtosecond is required. Clearly you do not want to run the simulator at 10^12 Hz or anywhere close to that. In my opinion there has to be an event driven approach where a sample is added as needed. The usual approach to cross from the signal domain to an event domain requires detecting signals crossing thresholds. One kludge is for the Boolean edge to start a timer and look for a crossing one femtosecond later. This is wasteful.