From a licence standpoint, EASA allows full credit of helicopter flight time up to 50% of that required for the ATPL i.e. of the 1500 hours needed, 750 can be in helicopters. From an operater perspective, looking at a command upgrade, that is up to them. Some may count in full, some at half rate others may discount entirely. a similar situiation exists for fast jet experience, where some airlines will factor the flight time when looking at the total.