You need to specify packed decimal as ZONED in the SQL*Loader Control file
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The precision of a numeric field is the number of digits it contains. The length of a numeric field is the number of byte positions on the record. The byte length of a ZONED decimal field is the same as its precision. However, the byte length of a (packed) DECIMAL field is (p+1)/2, rounded up, where p is the number's precision, because packed numbers contain two digits (or digit and sign) per byte.
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