Existing techniques have been characterized to align a given Nikon Body 7 exposure field to a larger Nikon Body 9 exposure field where the underlying Body 9 printed field area can be a non-integer multiple of the Body 7 printed field area. The enhancement of these techniques has been centered mostly upon the sampling plans of the Nikon alignment algorithms and the registration measurement sampling plans. Software provided by New Vision Systems has provided a cursory look into the performance of the technique used. This non-concentric phenomenon has been explored in several recent technical papers. Most previous works limited their analysis to integer non-concentric matching. Our study discusses a real manufacturing situation in a mature fab using the more flexible and economical technique of fractional field matching. On one particular device with not all the layers being interchangeable between Body 7 and Body 9 models, the non-concentric process decreased the number of exposure fields by 17.9 percent over the concentric process at the cost of additional overlay error. This additional error is not yet fully characterized, however can be between a 25-100 percent increase over the concentric process.