This is an example to explain @physicboy’s reply. The fundamental concept is that a native device in SPICE solves equations (e.g. Diode, Resistor etc…) and establishes input/output relationships at that simulation time. However, for a C++ block, its output can only be updated at the next simulation step (not during equation solving) [i.e. all device based on C++ block with this nature, including ¥-, €- and £-Device].
Therefore, within the C++ block, calculations are done exactly at that simulation time, but the output can only be updated at the next simulation time step. Generally, this explanation goes a bit beyond your initial question. In most cases, not being aware of this is not an issue, but it is crucial information to understand.
TimeInC.qsch (19.9 KB)
timeinc_x1.cpp (1.1 KB)
This is a reference
What triggers a C-block to run? - QSPICE - Qorvo Tech Forum