Monthly Financial statement help

We use Excel for our managers for their Yearly Income statements by month for several years. For instance, we will have 12 months of data for 2014, 12 months of data for 2015, but only 5 months for 2016. So with Column A being the accounts, column B is January 2014, C is January 2015, D is January 2016, E is February 2014, F is Feb. 2015, G is Feb 2016 and so on through AJ being December 2016 and AK through AM being year end totals. We also have several other tabs that are summary tabs including Gross Profit, Comparative Summaries, etc. The problem we're facing is that when we input new data we cannot figure out how to make it so that the formulas coincide with the month we want. So for our summary tabs we want to be able to simply select a month and have it use that month to do a Year to Date calculation. Right now what we have is all 12 months of 2014 and 2015 but only 5 of 2016 so the comparisons are vastly skewed. Is there a simple way for us to tell Excel what months to calculate and it will quickly populate our summary tabs when we want. We want it to calculate only specific months (i.e. January - March, or March - June, etc.). Any help or ideas would be appreciated!

DC

I have uploaded the spreadsheet we are hoping to get to fit our needs. To fill you in on the process, we would key in our data into the Red tabs for the month by store. We would like the summary tabs (and P&L Short) to be able to see what month has been keyed and then populate all three years for only certain months. So for instance on the spreadsheet only March 2016 has been keyed. We would like to be able to analyze just those months on the summary tabs. But when the second quarter information has been completed and keyed in, we would like to be able to only analyze April through June for 3 years ignoring the first quarter. The way it is set up now we will have to go in and change the formulas to only add those three months. Also when another month is keyed in we would like to see a running total from January through a certain month. Basically we want flexibility in analyzing our data by month without having to constantly change formulas. I have changed most of our numbers in the spreadsheet but the concept is still the same. Thanks for your help!

DC