Hi,
I’ve seen few things (bugs?) about the documentation and the get search tweets 
First : the param Since (YYYY-MM-DD) with the format date works ( Test on my application and it’s correct )and it’s not longer in the documentation
array (size=9) 'completed_in' => float 0.123 'max_id' => float 7.2051611793706E+17 'max_id_str' => string '720516117937061888' (length=18) 'next_results' => string '?max_id=720515839905165311&q=test%20since%3A2016-04-08%20until%3A2016-04-15&geocode=&lang=&count=100&include_entities=1&result_type=recent' (length=138) 'query' => string 'test+since%3A2016-04-08+until%3A2016-04-15' (length=42) 'refresh_url' => string '?since_id=720516117937061888&q=test%20since%3A2016-04-08%20until%3A2016-04-15&geocode=&lang=&result_type=recent&include_entities=1' (length=130) 'count' => int 100 'since_id' => int 0 'since_id_str' => string '0' (length=1)
Second : I can’t have access in the search_metada the since_id string and since_id always stays to zero ( beside refresh url has a since_id…)
I’ve tested this on my application and on your api console ( Api console result )
"search_metadata": { "completed_in": 0.14, "max_id": 720528237856743400, "max_id_str": "720528237856743424", "next_results": "?max_id=720528203639615488&q=test&include_entities=1", "query": "test", "refresh_url": "?since_id=720528237856743424&q=test&include_entities=1", "count": 15, "since_id": 0, "since_id_str": "0" }
If i make a request with the next_results the since_id and since_id_str stays on zero.
Any explanation make me happy 
