Inconsistent SP Performance On Different Servers

One of my developers recently installed a backup of the production database onto his test site. His test server has the same configuration as the production server.

One of the Stored Procedures that is called takes 1:45 to run on his machine, but only 2 seconds on the production server. This same SP takes only 2 seconds on my development database.

The SP is called iteratively, up to 10 times... to run against 10 separate fields. Depending on a value for a parameter called @CriteriaClassID, depends on which portion of the SP runs.

The significant difference in processing time in itself is baffling (since the servers are same specs / configuration, as far as I can tell, and the data is identical, since he has a backup of the most recent production data).

But more baffling: if, in his data, I switch the values from field 1 to field 2, and vice versa, his results take 2 seconds (switching the values in field 1 to field 2 switches the value in @CriteriaClassID which is passed through to this SP).

It's exactly the same SP; the only difference is that field 1 is processed first, field 2 second, field 3 third etc. On the production site and my development site, it doesn't make a difference in the order they are processed. On his machine it does.

Any ideas? I though perhaps his Indexes were corrupted in the rebuild, but we ran a SQL Server maintenance schedule to clean it up, and no improvement.

This is the SP, if it is of any help:

CREATE procedure [dbo].[st_pull_model_data] @ModelID as integer, @CriteriaID as integer
as

declare @ClientID as integer, @CriteriaClassId as char(1)

/*Procedure to pull data from org_model_data and postalcode_model_data for modeling and media analysis */
/*Need to have table #temp_data created outside of SP with fields org_id and zip_code */
/*This procedure is used by SP st_model_data */

If @CriteriaID is not null
begin

set @CriteriaClassId = (Select model_criteria_type from model_criteria where model_criteria_id = @CriteriaID)
if @CriteriaClassID = 'G' -- changes client_id from specific to general, if General is required.
begin
set @ClientID = 0
end
else
begin
set @ClientID = (Select client_id from model where model_id = @ModelID)
end

If @CriteriaClassId in ('G','P')
Begin
update#temp_data
setdata1 = postal_criteria_value
from #temp_data t
left outer join
(select postalcode, postal_criteria_value
from postalcode_model_data pmd
join model_org_trade_area mota on mota.zip_code = pmd.postalcode
join model_org mo on mo.model_org_id = mota.model_org_id
where model_criteria_id = @CriteriaID
and client_id = @ClientID
and mo.model_id = @ModelID) as PMD
onPMD.postalcode = t.zip_code
end
else
Begin
update#temp_data
setdata1 = org_criteria_value
from#temp_data t
left outer join
(select distinct postalcode, org_criteria_value, omd.org_id
from org_model_data omd
join org o on o.org_id = omd.org_id
join model_org_trade_area mota on mota.zip_code = omd.postalcode
join model_org mo on mo.model_org_id = mota.model_org_id and mo.org_id = o.org_id
where model_criteria_id = @CriteriaID and o.client_id = @ClientID and mo.model_id = @ModelID) as OMD
on OMD.postalcode = t.zip_code and omd.org_id = t.org_id
end
end