If you will read the bolded part below (as well as the rest) you will see that yes, you can have up to 6 months at a time without a job, HOWEVER, You must STILL earn at least a MINIMUM of 30K per annum. You have to fill out a form annually to report these amounts and if you fail to make the 30K you lose the PEP. Please see the reporting requisites in the last paragraph.
Conditions of Validity
Maximum Unemployment Period: This cannot exceed six continuous months at any point. This applies to PEP holders working in Singapore as well as PEP holders working on overseas stints assigned by their employers in Singapore. PEP holders who intend to leave Singapore and work for employers overseas should cancel their PEPs.
Minimum Annual Salary: PEP holders must earn an annual fixed salary of at least $30,000 for each calendar year of the PEP.
Requisite Notifications to MOM: PEP holders and their employers will need to keep MOM informed of each change in the PEP holders' employment status (e.g. commencement or cessation of employment) and agree to make available to MOM information on their annual fixed salary. PEP holders will also need to notify MOM of any changes in their contact details viz. local contact person and address.
Also, to note, it's only good for one issuance. If you fail to meet the requirement one year you lose the PEP forever. You cannot go on it and off of it for up to five years. It's issued ONCE and is good for UP TO a maximum of five years. After that? You will either have to go onto an employment pass or PR.