This is not true. 2015 freeze applied to all h1b applications including h1b transfers.
> Starting May 26, 2015, USCIS will temporarily suspend premium processing for all H-1B extension of stay petitions until July 27, 2015. During this time frame, petitioners will not be able to file Form I-907, Request for Premium Processing Service, for a Form I-129, Petition for a Nonimmigrant Worker, requesting an extension of the stay for an H-1B nonimmigrant.
In summary, yes the 2015 stay was just for extensions. No it wasn't for all applications.