Wjhy are you passing "0.0 MB" as Griowthrate????

IF Not Exists (Select Distinct DBName from #TempDBSize2

where DBName in (Select Distinct DBName from DBGrowthRate))

Begin

Insert into dbo.DBGrowthRate (DBName, DBID, NumPages, OrigSize, CurSize, GrowthAmt, MetricDate)

(Select tds.DBName, tds.database_ID, Sum(tds.Size) as NumPages,

Convert(decimal(10,2),(((Sum(Convert(decimal(10,2),tds.Size)) * 8000)/1024)/1024)) as OrigSize,

Convert(decimal(10,2),(((Sum(Convert(decimal(10,2),tds.Size)) * 8000)/1024)/1024)) as CurSize,

'0.00 MB' as GrowthAmt, GetDate() as MetricDate

from #TempDBSize2 tds

where tds.database_ID not in (Select Distinct DBID from DBGrowthRate

where DBName = tds.database_ID)

Group by tds.database_ID, tds.DBName)