The form 4562 is sent to the IRS in any year there is a change on that form. Explanations are not necessary at the time of filing. Speaking for the TurboTax program only, if explanations are required at the time of filing, the program will inform you of that. Otherwise, send only what is required. If additional information is needed by the IRS they will request it later. Trying to anticipate what the IRS wants is more apt to result in the same amount of delay as it would if one waited for the IRS to request it. It just depends on the human dealing with that specific return and how much attention they pay to details. Being that the IRS processes over 300 million tax returns within a 90 day period or less, it's uaually better to wait for them to ask for information.
