The USLE computed soil loss by A=RKLSCP, where an average annual value was computed for each factor.  With the exception of the interaction between the R factor and the C factor, not interaction between the USLE factors were considered.  The temporal scale used in computing the C factor was a crop stage period over which cover-management conditions were assumed to be represented by an average value for the period.  The length of crop stage periods typically ranged from a few days, like the rough plowed period in the spring, to a few months, like the after harvest period over the late fall, winter, and early spring.
	RUSLE1 considered additional interactions of the K and R factors and a partial interaction between P and R.  Also, the temporal time scale used in RUSLE1 was half month, and less if an operation occurred within a half month. This approach allowed a “paper version” of RUSLE1 to be used.
	However, while the mathematical techniques used in USLE and RUSLE1 were powerful and allowed paper versions, they were mathematically inaccurate by about 15 to 20% in several situations.  The proper mathematical procedure is to compute a daily value for each factor, compute a daily soil loss value, and add up the daily values to obtain a value for rotation.  RUSLE2 uses this mathematical procedure, which is a major change from both the USLE and RUSLE1.
	Although RUSLE2 computes an average annual value for the traditional USLE/RUSLE1 factors, those values are not used to compute soil loss.  In fact, multiplication of those values, as was done in the USLE and RUSLE1, will not give the RUSLE2 soil loss value.  The difference results from the far more proper mathematics in RUSLE2 than in the approximate mathematics in the USLE/RUSLE1.
	Small letters, rather than the traditional capitol letters, are used to distinguish the RUSLE2 approach from the USLE/RUSLE1 mathematical approach.
	The convention is that upper case letters in the USLE and RUSLE1 indicate average annual values while the lower case letters in RUSLE2 indicate daily values.