Why do you have different sheets for each Month?
How do show that you want to amortize for a particular month?
Can you post a concise example of a sheet?
In the quick example below G4 is Oct 1 2016
<b>Excel 2010</b><table cellpadding="2.5px" rules="all" style=";background-color: #FFFFFF;border: 1px solid;border-collapse: collapse; border-color: #BBB"><colgroup><col width="25px" style="background-color: #DAE7F5" /><col /><col /><col /><col /><col /><col /><col /></colgroup><thead><tr style=" background-color: #DAE7F5;text-align: center;color: #161120"><th></th><th>A</th><th>B</th><th>C</th><th>D</th><th>E</th><th>F</th><th>G</th></tr></thead><tbody><tr ><td style="color: #161120;text-align: center;">4</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;">Oct Balance</td></tr><tr ><td style="color: #161120;text-align: center;">5</td><td style=";">Name</td><td style=";">Terms</td><td style="text-align: right;;"></td><td style=";">Months</td><td style=";">Amount</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">6</td><td style=";">Chipotle</td><td style="text-align: right;;">01-01-16</td><td style="text-align: right;;">01-01-17</td><td style="text-align: right;;">12</td><td style="text-align: right;;">16,480.00</td><td style="text-align: right;;">1373.33</td><td style="text-align: right;;">4,120.03</td></tr></tbody></table><p style="width:1.2em;font-weight:bold;margin:0;padding:0.2em 0.6em 0.2em 0.5em;border: 1px solid #BBB;border-top:none;text-align: center;background-color: #DAE7F5;color: #161120">2e</p><br /><br /><table width="85%" cellpadding="2.5px" rules="all" style=";border: 2px solid black;border-collapse:collapse;padding: 0.4em;background-color: #FFFFFF" ><tr><td style="padding:6px" ><b>Worksheet Formulas</b><table cellpadding="2.5px" width="100%" rules="all" style="border: 1px solid;text-align:center;background-color: #FFFFFF;border-collapse: collapse; border-color: #BBB"><thead><tr style=" background-color: #DAE7F5;color: #161120"><th width="10px">Cell</th><th style="text-align:left;padding-left:5px;">Formula</th></tr></thead><tbody><tr><th width="10px" style=" background-color: #DAE7F5;color: #161120">D6</th><td style="text-align:left">=DATEDIF(<font color="Blue">B6-1,C6,"M"</font>)</td></tr><tr><th width="10px" style=" background-color: #DAE7F5;color: #161120">F6</th><td style="text-align:left">=ROUND(<font color="Blue">E6/D6,2</font>)</td></tr><tr><th width="10px" style=" background-color: #DAE7F5;color: #161120">G6</th><td style="text-align:left">=E6-DATEDIF(<font color="Blue">B6-1,G4,"M"</font>)*F6</td></tr></tbody></table></td></tr></table><br />