Dividing a Parcel with two Lots - Need Help getting second APN

[Emily Di]

If you have experience with within City of San Diego may I get your input? Got nowhere with DPI. I have a corner parcel. It's one APN comprising two "lots." The lots runs longways from the west/narrowest street front (each about 25 x 110) to the alley. The dwelling units span both lots. I want to adjust the lots to run short way from the south/long street side so that each is ~50x55. The end goal is to have 2 separate saleable lots. There are at least 20 APN's on my street that have done this. My zoning is RM1-3. 

The info I got from DPI was: my lot would be nonconforming so it's not possible (because it would be 55 deep and code is 90 deep. When I showed them others on the street that had done this DPI said it was "old zoning." When I showed them a property that had done it within the last year (although not corner) DPI said it was because they had demolished the building which was "merging" the lots and therefore "got their lots back." DPI said that would be my option but it would leave me with long narrow lots versus the square lots I'd like. 

Has anyone done anything similar who can provide perspective? Did I get the right advice from DPI or is there another way? Today I received an email from another investor describing a potential deal which said "it's on a corner with alley access, can leverage new zoning laws that would allow for a lot split..." What are the "new zoning laws? 

 @David F. & @Justin R. & @Colin L. because I didn't want to hijack your thread David, but appreciate any advice.