Help with Report for Item Sales grouped by Menu item Group but with portion breakdown

[JTRTech]

@JTRTech

@{REPORT ORDER DETAILS:O.ItemGroup.asc,O.ExactTotal.Sum::{0}:,}
@{REPORT ORDER DETAILS:O.MenuItemName,O.ExactTotal.Sum.desc:(ODI=True):{0}:,}
[$1 Sales:8, 2, 2, 2]
>{REPORT ORDER DETAILS:O.MenuItemName,OS.NewBook GLA,O.Quantity.Sum.desc,O.ExactTotal.Sum.desc:(ODI=True) and O.MenuItemName=“$2” and (MG=$1)}
{REPORT ORDER DETAILS:’ ‘+[O.PortionName],’',O.Quantity.Sum.desc,O.ExactTotal.Sum.desc:(ODI=True) and O.MenuItemName=“$2” and (MG=$1) and O.PortionName!=“Normal”}
>>Total $1||{REPORT ORDER DETAILS:O.Quantity.Sum,O.ExactTotal.Sum:(ODI=True) and (MG=$1)}

Am finding this report takes a LONG time to generate when running for monthly stocktake, any suggestions of ways to improve speed?
I expect because its looping through ALL orders for reach portion of product so if 100 products thats 100 loops of all orders for the month…
Understand why that would be a lengthy process but perhaps a twerk could improve performance.
@emre - know your busy, any suggestions?