You may find the exchange at How to convert an integer (int, Short, Long, Float, Double) to String - #7 by John_Carter4 to be of interest.
It appears the absolute service (and possibly others) try to use BigDecimal to avoid the inherent inaccuracies of float/double but then subvert that effort by having an intermediate double type.
Likely need to follow the suggestion from @Sreekanth_Siddapur_Channakeshava to create your own replacement that avoids using float/double at any step. Here is simplistic code that is not as robust in terms of the input handling as the built-in service, but does not have a double in the mix.
IDataCursor idc = pipeline.getCursor();
String number = IDataUtil.getString(idc, "number");
IDataUtil.put(idc, "positiveNumber", new java.math.BigDecimal(number).abs().toString());
idc.destroy();