Help with HMRC PAYE Software & Pension contributions

JoJo21

Payroll is not a big part of my job so I only use the HMRC PAYE tools but I have a client who has just signed their weekly paid employee up to a pension, both the employer and the employee each contributing £10 per week. The letter from the pension provider states that the Employee payment is net, yet the Employer payment is gross. Not really sure what this means, how do I enter this on the PAYE software. Will the earnings for tax be £10 less so, say £250 instead of £260 and the earnings for NIC's £260? Please help, I'm having a mental block!