On an average recovery test, an Adept character heals as follows:

<table border=1>
 <tr>
  <th>Recovery Roll</th>
  <th>Average HP Healed</th>
 </tr>
 <tr>
  <td>3</td>
  <td>0.0080</td>
 </tr>
 <tr>
  <td>4</td>
  <td>0.0320</td>
 </tr>
 <tr>
  <td>5</td>
  <td>0.0880</td>
 </tr>
 <tr>
  <td>6</td>
  <td>0.2000</td>
 </tr>
 <tr>
  <td>7</td>
  <td>0.4000</td>
 </tr>
 <tr>
  <td>8</td>
  <td>0.7040</td>
 </tr>
 <tr>
  <td>9</td>
  <td>1.1360</td>
 </tr>
 <tr>
  <td>10</td>
  <td>1.7040</td>
 </tr>
 <tr>
  <td>11</td>
  <td>2.4000</td>
 </tr>
 <tr>
  <td>12</td>
  <td>3.2000</td>
 </tr>
 <tr>
  <td>13</td>
  <td>4.0880</td>
 </tr>
 <tr>
  <td>14</td>
  <td>5.0320</td>
 </tr>
 <tr>
  <td>15</td>
  <td>6.0080</td>
 </tr>
 <tr>
  <td>16</td>
  <td>7.0000</td>
 </tr>
 <tr>
  <td>17</td>
  <td>8.0000</td>
 </tr>
 <tr>
  <td>18</td>
  <td>9.0000</td>
 </tr>
 <tr>
  <td>19</td>
  <td>10.0000</td>
 </tr>
 <tr>
  <td>20</td>
  <td>11.0000</td>
 </tr>
 <tr>
  <td>21</td>
  <td>12.0000</td>
 </tr>
 <tr>
  <td>22</td>
  <td>13.0000</td>
 </tr>
 <tr>
  <td>23</td>
  <td>14.0000</td>
 </tr>
</table>


Where "Recovery Roll" is usually your HT, but has +6 if you've taken a Booster Potion.
Given this, I think an Extra Recovery Test should be about a 5 point advantage, available for double cost after character creation, available for normal cost when going up in circle if it's appropriate to that instance of the Discipline. 

Oh, and the "Rapid Healing" advantage which gives a +5 to Recovery Tests but costs only 5 points is going to have to get more expensive --- if it's allowed at all.  Anybody who has it should give themselves "Extra Recovery Test" instead.  --bts