Overflow fixes?

src/pow.cpp

@@ -349,13 +349,13 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
         if ( ASSETCHAINS_ADAPTIVEPOW == 1 ) // TSA
         {
             arith_uint256 A,B,C; // fix overflow bug on diff stranding
-            if ( tipdiff < 2 )
-                tipdiff = 2;
+            if ( tipdiff < 3 )
+                tipdiff = 3;
             bnTarget = ct[0] / arith_uint256(K*T);
             A = bnTarget * arith_uint256(T);
-            B = (bnTarget / arith_uint256(360000)) * arith_uint256(tipdiff * zawy_exponential_val360000(tipdiff/2));
-            C = (bnTarget / arith_uint256(360000)) * arith_uint256(T * zawy_exponential_val360000(tipdiff/2));
-            bnTarget = (A + B - C) * arith_uint256(K*T) / arith_uint256(tipdiff);
+            B = (bnTarget / arith_uint256(360000)) * arith_uint256(tipdiff * zawy_exponential_val360000(tipdiff*5/9));
+            C = (bnTarget / arith_uint256(360000)) * arith_uint256(T * zawy_exponential_val360000(tipdiff*5/9));
+            bnTarget = ((A + B - C) / arith_uint256(tipdiff)) * arith_uint256(K*T);
             {
                 int32_t z;
                 for (z=31; z>=0; z--)