Unable to assign MINUS to duration in add-ons

[Valentina R]

People use add-ons to add or reduce the price and duration. The price works ok both ways but the duration only works for PLUS. Iff a MINUS is added to the number, it simply ignores it and add the duration instead.

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Reported here.

[Željan Topić]

Fixed with 4.6.0. It was set so duration cannot get below default duration. From 4.6.0 it will revert to default duration, when duration is zero or negative.