Differences between San Pablo Güilá Zapotec and San Dionisio Ocotepec Zapotec

In the Ethnologue classification of languages, San Pablo Güilá Zapotec and San Dionisio Ocotepec Zapotec are supposed to be two dialects of the same language.  (They both have the Ethnologue code ztu).

These two towns are both located in the southern Tlacolula Valley area of Oaxaca and they are adjacent to each other.  The main source of information I have for Güilá is the 2009 dissertation of Francisco Arellanes.

[Arellanes, Francisco. 2009. El sistema fonológico y las propriedades fonéticas del zapoteco de San Pablo Güilá. Descripción y análisis formal. Tesis doctoral. Colegio de México.]

However, as I work through this thesis, it becomes clearer to me that the Güilá and San Dionisio varieties are more different from each other than you might expect if they were simply dialects.

Some differences:

• Presence of a /ɨ/ phoneme in Güilá.  There is no phonemic /ɨ/ in San Dionisio, though [ɨ] appears as an allophone of /i/ after /ts/ and /dz/ affricates.   Sample contrasts : 

1. Güilá gɨ:ʒ 'roncha (spots on the skin)' Arell. p 150/ San Dionisio ge:dʒ 'grano (pimple)'
2. Güilá mɨ:lj 'dinero (money)'/San Dionisio me:lj

• Affricates /dz/ and /dʒ/ in San Dionisió; these have simplified to /z/ and /ʒ/ in Güilá.   (This is a sound change that Güilá shares with other Zapotec such as San Lucas Quiaviní Zapotec.) The previous example also shows this correspondence

1. Güilá gɨ:ʒ 'roncha (spots on the skin)' Arell. p 150/ San Dionisio ge:dʒ 'grano (pimple)'
2. Güilá na:ʒ 'mojado (wet)'/San Dionisio na:dʒ

• Fortis L is /ld/ in San Dionisio but /l/ or /lθ/ in Güilá in at least some positions (syllable final only?)

1. Güilá bel: 'pescado (fish)'/San Dionisio beʰld

• Other kinds of changes (affecting loans)

1. Güilá btʃar 'spoon'/San Dionisio kutʃarr 'spoon' (< Spanish cucharra 'spoon')
2. Güilá ta:ɸ 'cuento (account)'/San Dionisio ta:bl (< Spanish tabla 'table) 
3. Güilá pun: 'punta (first pressing of mezcal)'/San Dionisio punt (<Spanish punta)

[BTW, I do not really understand the semantic shift here; possibly there are meanings of cuento and tabla in Spanish that are more similar to each other that I am unaware of?]