add note about the smaller gap before the first heroic success

apps/cortex_prime.html

@@ -702,7 +702,8 @@ <h2>Notes</h2>
         <ul>
             <li>If more dice are specified to be dropped and/or kept than there are in the pool, the excess kept dice do not contribute to the total.</li>
             <li>"Drop" is used for e.g. the Burst SFX and removes the highest-rolling dice before keeping among the rest. In case of a tie, the smaller die is removed.</li>
-            <li>Remember that the second roller loses ties, dice that roll a 1 (hitch) can't be used for the total or effect, and there is always the option to have a "free" d4 effect.</li>
+            <li>Remember that the roller loses ties, dice that roll a 1 (hitch) can't be used for the total or effect, and there is always the option to have a "free" d4 effect.</li>
+            <li>Because the roller loses ties, the difference between a normal success and the first heroic success is 4 rather than 5.</li>
             <li>On the "exactly" plot, the effect die curves show the chance of rolling exactly a total while keeping an effect die of <b>at least</b> that size.</li>
             <li>On the "at least" plot, the vertical <b>position</b> of each effect die <b>curve</b> at a particular total is the chance of achieving that total while keeping an effect die of <b>at least</b> that size.</li>
             <li>On the "at least" plot, the vertical <b>extent</b> of each effect die <b>area</b> at a particular total is the chance of achieving that total while keeping an effect die of <b>exactly</b> that size.</li>