2 question about solr and lucene

Hi, guys:
    I met two questions about solr and lucene, wish people to help out.

use payload query but can NOT with numerical field type.  for example:                
        I implemented my own requesthandler, refer to http://hnagtech.wordpress.com/2013/04/19/using-payloads-with-solr-4-x/ 
         I query in solr:    sinaTag:operate
          solr response:

      "numFound": 2,
   "start": 0,    "maxScore": 99,    "docs": [      {        "id": "1628209010",
        "followersCount": 752,
        "sinaTag": "operate|99 C2C|98 B2C|97 OnlineShopping|96 E-commercial|94",
        "score": 99

           },

      {        "id": "1900546410",
        "followersCount": 1002,
        "sinaTag": "Startup|99 Benz|98 PublicRelation|97 operate|96 Activity|95 Media|94 AD|93 Vehicle|92 ",
              "score":   96

           }

        This work well. 
        But query with combined with other numberical condition, such as:
        sinaTag:operate and followersCount:[752 TO 752]
        {        "responseHeader": {        "status": 0,        "QTime": 40      },      "response": {        "numFound": 0,        "start": 0,        "maxScore": 0,        "docs": []      }
   }
   According these dataset, the first record should be responsed rather than NOT FOUND.
   I not know why.


 2. About string field fuzzy match filtering, how to get the score? what the formula is?
    When I used two or several string fuzzy match, probable AND or OR,  how to get the score? what the formula is?
    Might I implement myself score formula class which interface or abstract class to extend ?
   
        



Thanks in advance.