minor updates in the decay function explanation

tips/TIP-0039/tip-0039.md

@@ -194,8 +194,9 @@ thus, its definition is explained here just for the sake of clarification. The v
 
 The lookup table is an integer approximation of <code>2<sup>Decay Factors Exponent</sup>Decay per
 Epoch<sup>n</sup></code>, for different values of `n` ranging from 1 to `Decay Factors Length`. 
-To obtain the decayed value of a certain amont of Mana `M` after `n` epochs has been passed, one should multiply 
+In general lines, to obtain the decayed value of a certain amont of Mana `M` after `n` epochs has been passed, the basic idea is to multiply 
 `M` by the entry of `Mana Parameters::Decay Factors` relative to `n` and then execute a right shift of `Decay Factors Exponent` bits.
+However, in some cases, a slighly more complex algorithm must be used, which we define in the next section.
 
 ### Decay Function