When heating two items separately in a microwave, the heating time specified for each item is typically based on the assumption that only one item is being heated at a time. Therefore, if you attempt to heat both items simultaneously, the total heating time will likely be longer than the individual times specified.
The exact additional time required when heating two items together will depend on various factors, including the power of the microwave, the size and quantity of the items, and the microwave's ability to distribute heat evenly. It's challenging to provide an exact time without specific information on these factors.
Regarding the identical or non-identical nature of the items, it can affect the heating time to some extent. If the two items are identical in size, shape, and temperature before heating, they will likely heat more evenly and require a similar amount of time to heat compared to heating them separately. However, if the items differ in size or temperature, the heating time may vary, and one item might finish heating before the other.
To determine the actual heating time for two items in your specific microwave, it is recommended to monitor their progress closely and adjust the heating time as needed. You may need to experiment with different time intervals to achieve the desired level of heating for both items simultaneously.