Why does a MOD ID with a depth over 15" require two TEPs?

Short answer: 
Because of panel sizing, cutting limitations, and material loss during the cutting process, deeper modifications require more material. 

Detailed explanation: 
Each TEP panel starts as a fixed size: 30" wide by 96" long. When a cabinet depth is modified, four new panels must be cut from the TEP material. 

• For depths of 15" or less: 
  One TEP can be split efficiently to create enough usable material for all four panels, so only one TEP is required. 
• For depths over 15" (such as 24"): 
  The panel can no longer be divided evenly. Cutting wider sections creates unavoidable scrap and reduces the total usable length. In many cases, this means there is not enough material to produce all four panels from a single TEP. 
• Cutting tolerances also matter: 
  Even when the panel measurements appear to add up to 96", the cutting process itself uses material. Each cut removes a small amount of material (the width of the saw blade), so the final usable length is slightly less than the starting size. Because of this, layouts that work on paper often cannot be produced from a single TEP in practice. 

While a few smaller cabinets may still be able to use one TEP at deeper depths, our system cannot reliably identify those exceptions. To ensure consistent results and accurate billing, we require two TEPs for all depth modifications over 15".