A corp. made numerous contributions to their DB Plan during the months of January thru September 2018. These contributions can either be used for the 2017 year-(of course must be within the min/max range) (as made by extended due date of 2017 return -sept. 15, 2018) or for the 2018 year. Question: Can you use contributions made in January, February, and June 2018 for the 2017 tax year and then use contributions that were made in March, April and May 2018 FOR THE 2018 tax year, or must you go in order (ie contributions made from Jan thru April 2018 for the 2017 tax year and then contr. made from May 2018 thru Sep 2018 for the 2018 tax year). Thank you.