Piaggio P.112 was a variant of P108 with Piaggio P.XXII engines.
(from http://www.csd.uwo.ca/Elevon/gustin_military/db/ital/P112PIAG.html)
Piaggio P.113 an other variant of P108 with poweful engines ( no more detail)
(http://www.csd.uwo.ca/Elevon/gustin_military/db/ital/P113PIAG.html)
Piaggio P.114 was version idro of Piaggio P.112 : little curiosity, there was a proposal build first eight prototypes of Piaggio 108 B like Piaggio P.114 ( idro - version) ( from " Aerei nella Storia" of August 2008 , article about Piaggio 133 project).
(from http://www.csd.uwo.ca/Elevon/gustin_military/db/ital/P112PIAG.html)
Piaggio P.113 an other variant of P108 with poweful engines ( no more detail)
(http://www.csd.uwo.ca/Elevon/gustin_military/db/ital/P113PIAG.html)
Piaggio P.114 was version idro of Piaggio P.112 : little curiosity, there was a proposal build first eight prototypes of Piaggio 108 B like Piaggio P.114 ( idro - version) ( from " Aerei nella Storia" of August 2008 , article about Piaggio 133 project).